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Biomedical subjects

R Eckhardt

Publications and source records attributed to R Eckhardt.

At least 19 recordsLinked to original sources
PubMed2005

Towards a Mobile Intelligent Information System with Application to HIV/AIDS.

The United Nations Security Council reports HIV/AIDS as the fastest growing threat to human development. In addition, the World Health Organization [1] reports that nearly 5 million persons (4.3 million adults and 700,000 children) are newly infected with HIV each year; more than 95% of them found in developing countries. Since STDs as a group are a personal problem which few people feel comfortable discussing, we believe that hand-held PDAs can provide an opportunity for learning about this disease while insuring anonymity. This device will employ the newest technologies including Bluetooth wireless technology, which can transmit and receive data via a short-range radio link using a globally available frequency band (2.4 GHz ISM band), enabling rapid and accurate synchronous and asynchronous data communication. The first generation of Bluetooth permits exchange of data up to a rate of 1 Mbps, even in areas with much electromagnetic disturbance. This emerging technology can facilitate HIV/AIDS outreach around the globe.Recent advances in learning have taken a particularly cognitive perspective and these findings have implications for education in general as well as for the development of intelligent tutoring systems in particular. In the past, effective SmartBookstrade markhave been developed for AIDS education to disseminate the critical knowledge relevant to this epidemic [2].Since 1993, the proliferation of the World Wide Web has created a plethora of new opportunities for the delivery of electronic distance learning systems. However, we feel that it is important that a whatever technology is employed is based on a sound educational theory. A new, comprehensive, web-based learning system called SmartTutor has been developed, at Brooklyn College of The City University of New York [3]. This technology provides a user-friendly, self-paced, easy to modify, software environment intended to serve the user's learning needs and is based on a generic SmartTutor methodology organized around the use of concept mapping. Early assessment of SmartTutor has shown that it is well received by students and helps significantly in their learning processes. It is readily adaptable to the presentation of academic and more general subject matter such as the latest available information on HIV/AIDS. Our new HIV/AIDS SmartTutor will incorporate this SmartTutor paradigm. Our new SmartTutor would provide worldwide access to medical professionals as well as the general public to learn about HIV/AIDS. This new device could also provide a survey tool to facilitate HIV risk assessment. Demonstrations of the SmartTutor learning system will be presented and the continued development of the applications will be discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1999

A decision technology system for health care electronic commerce.

Mounting costs have escalated the pressure on health care providers and payers to improve decision making and control expenses. Transactions to form the needed decision data will routinely flow, often electronically, between the affected parties. Conventional health care information systems facilitate flow, process transactions, and generate useful decision information. Typically, such support is offered through a series of stand-alone systems that lose much useful decision knowledge and wisdom during health care electronic commerce (e-commerce). Integrating the stand-alone functions can enhance the quality and efficiency of the segmented support, create synergistic effects, and augment decision-making performance and value for both providers and payers. This article presents an information system that can provide complete and integrated support for e-commerce-based health care decision making. The article describes health care e-commerce, presents the system, examines the system's potential use and benefits, and draws implications for health care management and practice.

Commerce↗
PubMed1994

Metabolic and hemodynamic changes during isokinetic muscle training. A controlled clinical trial.

Twenty-one healthy males aged 20-36 years were examined for hemodynamic and metabolic parameters such as heart rate, oxygenation, lactate, blood pressure, under isokinetic and ergometric loadings. The healthy volunteers were tested by increased loads and constant times with an identical isokinetic and ergometric power. The important results are: Heart frequency and blood pressure are higher under isokinetic than under ergometric conditions. Oxygenation is equal in both tests. The lactate values show for the isokinetic maximal and for the ergometric submaximal loadings. The definitive factor for this variation is the relation between force and velocity. The higher tension of the muscles and the higher activity of the fast-twitch fibers seem to be responsible for the increasing of sympathicotonia. The clinical impact of this controlled study is: 1. Isokinetic testing might be dangerous for patients with cardiac diseases or circulatory disturbances. 2. Isokinetic training programs have to pay attention to joint and internal diseases at the same level. 3. During the first isokinetic test all precautions for a possible emergency case have to be taken.

Adult↗
PubMed1994

[The importance of neuromuscular coordination for athletic stress of the knee joint after anterior cruciate ligament injuries. A gait and locomotion analysis with EMG on treadmill].

Anterior cruciate ligament (ACL) injuries are considered of high prevalence in sports medicine and are of socio-economical relevance. Indications for operative treatment and the ability for physical activity after ACL injuries are discussed controversially. Although it is known that the ACL has neurosensory functions, no test system has been developed which takes this biological function into account. The first goal of this study was to determine the neurosensory function after ACL reconstruction, and the second goal was to develop predictive markers for functional results after surgery. 20 healthy athletes (10 male, 10 female) (control group) and twenty ACL deficient patients (10 male, 10 female) (study group) were included in a prospective, controlled study. Electromyograms (EMG) were performed under defined load conditions of the knee. Important results of our study are: 1. Previously described parameters can be reproduced with EMG techniques. Their validity was proved. Typical contraction patterns (m. quadriceps, hamstrings, m. gastrocnemius) for defined load conditions can be recorded. 2. Statistically significant differences can be shown between the control group and the study group as well as between the two legs (injured/noninjured) of the same patient in the study group. 3. The results suggest that the diminished innervation of the m. biceps femoris and m. gastrocnemius in down-ramp-running as an important parameter for ACL deficiency. 4. Distinct differences of innervation patterns of the muscles, which stabilise the knee in downramp walking suggest that despite a subjective stability, altered load conditions may result. Innervation patterns seem to vary from individual to individual. 5. Concluding from our findings, we suggest that clinical methods should be developed to allow a patient-specific assessment of physical activity.

Adult↗
PubMed1992

Deuterium oxide (heavy water) arrests the cell cycle of PtK2 cells during interphase.

Deuterium oxide (D2O, heavy water) exerts an antiproliferative effect on a variety of cells in vitro and on some organisms. This effect is mainly ascribed to a tubulin-mediated antimitotic action. We evaluated the morphology, the mitotic activity, and the dynamics of the cell cycle of PtK2 cells grown in vitro in the presence of 75% D2O for up to eight weeks by microspectrophotometric DNA measurements as well as flow cytometric analysis and a determination of mitotic indices. Substitution of heavy water for water in the culture medium initially increased the mitotic index by a (pro-) metaphase block but after 2 to 3 days of incubation no mitotic figures were seen. Analysis of cells grown for 6 days in medium containing 75% D2O revealed accumulation of cells in S/G2-phase. Extended treatment stabilized the high level of cells in this specific phase, when compared to normal growing cells. Cells grown for 1 to 6 weeks in the presence of D2O remained non-proliferating, nevertheless, they were able to divide again after recovery in non-deuterated medium. The time needed for resumption of the mitotic activity was proportional to the duration of deuterium oxide exposure. Cells incubated for 8 weeks in 75% D2O did not recommence mitotic activity. Light and electron microscopic examination revealed characteristic morphological changes of size and ciliation in PtK2 cells subjected to prolonged deuteration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

DNA index and cell cycle analysis of primary breast cancer and synchronous axillary lymph node metastases.

The DNA Index (DI) and the percentage of cells in S-phase (S-phase fraction, SPF) were measured by flow cytometry in 80 primary breast carcinomas and in 80 accompanying axillary lymph node metastases. The DI in primary tumors and metastases agreed in 61 cases (76%). Cases with diploid primary tumors revealed more constancy of the DI in comparison to the metastases than the cases with aneuploid primary tumors (91% and 70% respectively). The mean values of the SPF were in close agreement in the primary tumors and in the lymph node metastases (6.1% and 6.0% respectively). Differences between the SPF of the two groups could be detected only by the consideration of case-related data pairs. In 50 cases (62%), the percentage of SPF agreed approximately in primary tumors and in the correspondent metastases. The cases with diploid primary tumors revealed more agreement of the SPF in the primary site and the metastases than did cases with aneuploid primary tumors (78% and 56% respectively). In conclusion, diploid carcinomas and their metastases revealed more constancy of the DI and the percentage of SPF than aneuploid carcinomas. These findings agree well with a better prognosis of diploid mammary carcinomas, as reported in the literature. Comparisons between the DI and the SPF in primary tumors and the corresponding metastases could be a source of valuable information on the biological behaviour and the aggressiveness of mammary carcinomas.

Aneuploidy↗
PubMed1989

Influence of the elimination of lymphocytes from tumor cell suspensions on the calculation of S-phase fractions by flow cytometry.

Contaminating lymphocytes were eliminated from enzymatically obtained cell suspensions of 260 surgical biopsy specimens by density gradient centrifugation using lymphocyte separation medium (LSM) in an attempt to improve the determination of S-phase fractions by flow cytometry. The elimination of lymphocytes from the cell suspensions was ascertained on cytologic smears prepared from the suspensions before and after LSM centrifugation. Following the elimination of lymphocytes, the calculated S-phase fractions increased significantly in DNA-diploid tumors, but not in DNA-aneuploid ones. The increase of the S-phase fraction was correlated to the numbers of lymphocytes in the tumor cell suspensions before LSM centrifugation. Furthermore, in 12 tumors originally classified as diploid, an aneuploid cell line was detected after LSM centrifugation. These results indicate that samples from diploid tumors containing large numbers of lymphocytes should have the lymphocytes eliminated by methods such as LSM centrifugation in order to obtain reliable results for the calculations of the S-phase fractions.

Breast Neoplasms↗
PubMed1986

A case of Sjögren's syndrome with severe anemia due to myelitis.

An unusual case of Sjögren's syndrome presenting with severe anemia as the predominant clinical feature is described. Histological examination of a bone marrow biopsy specimen demonstrated that the patient's anemia was caused by myelitis and vasculitis of the small intraosseous vessels. Our report might stimulate a more thorough investigation of bone marrow in patients with connective tissue diseases and anemia.

Anemia↗
PubMed1984

[Polycythemia in kidney cysts. A report on an unusual case].

A 43-year-old woman with a solitary renal cyst developed polycythaemia. 21 well documented cases of this type have been previously published. In the majority of them a causal connection could be assumed between the renal cyst and polycythaemia: in 13 of the 15 cases (as in the reported one), the polycythaemia disappeared after surgical removal of the cyst. Measurement of serum erythropoietin can help in the differential diagnosis, but exclusion of polycythaemia vera may be difficult in the individual case.

Adult↗
PubMed1984

[Systemic lupus erythematosus. Brown-Sequard syndrome, spinal ataxia and peripheral polyneuropathy as the sole manifestations].

Neurologic manifestations were the sole symptoms of disease in three patients with systemic lupus erythematodes (SLE): one case presented with Brown-Séquard's syndrome, a second with spinal ataxia and polyneuropathy, and a third with polyneuropathy. In all three patients there was a considerable delay in making the diagnosis after onset of neurological symptoms. The diagnosis was established either by demonstration of antinuclear antibodies in combination with antibodies against dsDNA or by the demonstration of antibodies against dsDNA alone. In two patients perivascular deposits of IgG and C3 were seen in skin-muscle biopsies from the calf region.

Aged↗
PubMed1983

[Immunologic parameters in pericholangitis and primary sclerosing cholangitis with and without ulcerative colitis].

Immunological parameters and histocompatibility antigens (HLA) were determined in seven patients with non-bacterial cholangitis. Four patients had pericholangitis and ulcerative colitis, three had primary sclerosing cholangitis, one of these with ulcerative colitis. All 7 patients had antinuclear antibodies; however, there were no antibodies against DNA, against mitochondria or liver membrane antigens. One patient had low-titre rheuma factors. Immunoglobulins G, A and M and complement components C3 and C4 were mostly in the normal range. HLA constellation was positive for B8 in 6 patients. These were male patients with disease manifestations between the 12th and 45th year of life. The results support the concept that pericholangitis and primary sclerosing cholangitis with or without ulcerative colitis are related hepatological disease entities with an immunological pathogenesis and an underlying genetical determination.

Adult↗
PubMed1982

Comparative DNA/DNA reassociation kinetics in three hamster species.

1. Three major DNA repetition classes can be distinguished in the genomes of three hamster species Mesocricetus auratus, Cricetulus griseus, and Phodopus sungorus sungorus: A very fast reassociating fraction of about 13% of the DNA, a fast reassociating fraction comprising 10-23% of the DNA, and a slowly reassociating fraction containing single-copy sequences of 63-78% of hamster DNA. 2. In the DNA of the Syrian and Djungarian hamster 43%-53%, and in the DNA of the Chinese hamster 80% of the single-copy sequences are interspersed with repetitive sequences. 3. The lengths of repetitive DNA sequences, vary between more than 3 kb and 0.3 kb, with the majority of sequences having a length of 0.3 kb to 0.5 kb. 4. The findings suggest that the genomes of the hamster species studied are organized in a short period interspersion pattern. 5. Unlike other vertebrate and invertebrate genomes, moderately repetitive sequences exhibit a high degree of intraspecific homology in the hamster genome.

Animals↗
PubMed1981

[Endometriosis of the terminal ileum: differential diagnosis to the Crohn's disease (author's transl)].

We report on the clinical course of a 30 year old female patient with endometriosis of the terminal ileum. The course was complicated by development of intestinal abscesses, entero-cutaneous and entero-vesical fistulas and stenosis of the terminalö ileum. A diagnosis of Morbus Crohn was made and was only corrected after the patient had to be operated upon because of mechanical obstruction of the terminal ileum. The problems of diagnosis and management are presented.

Adult↗