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Biomedical subjects

A Hilgers

Publications and source records attributed to A Hilgers.

3 recordsLinked to original sources

Approach to Gaussian stochastic behavior for systems driven by deterministic chaotic forces.

We consider skew-product dynamical systems that describe the stroboscopic dynamics of a damped particle subjected to a chaotic kick force. In a suitable scaling limit the dynamics converges to the Ornstein-Uhlenbeck process. We investigate the deterministic chaotic corrections in the vicinity of this Gaussian limit case for various examples of chaotic forces. We present numerical evidence that, for certain classes of chaotic forces, the deterministic chaotic corrections of the invariant density are universal. We provide analytical results for forces generated by Tchebyscheff maps and sketch a renormalization group theory in the space of probability densities.

Journal Article↗

[Chronic fatigue syndrome: immune dysfunction, role of pathogens and toxic agents and neurological and cardial changes].

375 patients with chronic fatigue syndrome (CFS) were examined using a standardized questionnaire and subsequent interview on 11 risk factors and 45 symptoms. Additionally immunologic, serologic, toxicologic, neuroradiologic, neurophysiologic and cardiologic investigations were performed. Immunologic tests showed cellular immunodeficiences particularly in functional regard (pathological lymphocyte stimulation in 50% of the patients, disorders of granulocyte function in 44%). Furthermore variable deviations were found in the lymphocyte subpopulations (CD3, CD4, CD8, CD19, DR, Leu 11 + 19). In the humoral part tendencies to low IgG-3- and IgG-1-subclass-levels occurred (59% respectively 11% of the patients) also as decreases in complement system (CH50, C3, C4, C1-esterase-inhibitor). In the group of activation markers and cytokines 42% of the investigated patients had circulating immune complexes (CIC), 47% increases of tumor-necrosis-factor (TNF-a) and 21% increases of soluble interleukin-2-receptor (IL-2-R). The increased occurrence of autoantibodies in the CFS-patients (specially antinuclear anti-bodies [ANA], microsomal thyroid antibodies) suggest, that CFS is associated with or the beginning of manifest autoimmune disease. Under the pathogens 78% of the patients had a striking serological constellation of Epstein-Barr-Virus (EBV-EA positive, low EBNA-titers), in the HHV-6-Virus 47% showed increased antibody-titers. Tests on further herpes viruses and on Borreliae, Chlamydiae, Candida and Amoebae were positive in 8 to 36% of the examined patients. Furthermore there were found variable deficits of vitamins and trace elements also as hormonal disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Postinfectious chronic fatigue syndrome: case history of thirty-five patients in Germany.

Thirty-five patients with chronic fatigue syndrome according to the criteria of Holmes were followed for periods of up to eight years. The most frequent symptoms were severe fatigue, arthralgias and myalgias, recurrent oropharyngitis and various psychiatric disorders. More than half of the patients suffered from neuropathy, lymphadenopathy, gastrointestinal complaints and recurrent low-grade fever. Recurrent or persistent activity of human herpesvirus -6 infection was seen in 73% of the patients and of Epstein-Barr virus in 34.4%. In addition, various other infections were diagnosed at lower frequency. Initial routine immunologic screening revealed various types of deficiencies, these were yet inconsistent and variable when different patients were compared with each other. Tentative treatments included in immunoglobulins, nonspecific immunostimulation and virostatic drugs. No consistently positive results were obtained with any treatment schedule although immunoglobulins appeared the most efficient measure. In addition, psychologic care of the patients is indicated, since disturbances in the psycho-neuroimmunologic regulation may play a significant role in the pathogenesis of the disease.

Adult↗