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Biomedical subjects

G Reimann

Publications and source records attributed to G Reimann.

At least 19 recordsLinked to original sources

[Off-label use in dermatological practice. The conflict between professional duty and legal requirements].

When making therapeutic decisions, doctors often find themselves faced with a dilemma regarding ethical, professional, legal liability, social and service aspects of their duties. These conflicts may be enhanced when medications have to be prescribed for non-approved usages, known as off-label prescribing, because existing therapy options have been exhausted. This option become considerably more difficult since the German Federal Social Court decision of March 2002 which limited off-label use to a number of very strictly defined circumstances. In order to clarify the basis for taking decisions in a given situation, an oncology expert commission has been formed under the coordination of the Department of Health and Social Security. However, this is no solution for the great variety of uncommon dermatological diseases which often require off-label medication usage.

Clinical Trials as Topic↗

[HIV/AIDS competence network research group presents first results].

Germany's clinical HIV research efforts are underrepresented on an international level. This deficit is primarily due to a lack of clinical studies involving patients from across the country and the fact that no national patient cohort system exists in Germany which could provide a basis for such clinical studies. The competence network HIV/AIDS is filling this shortcoming by serving as a comprehensive, nationwide research alliance. The establishment of a patient cohort is linked to 20 projects. The success of this new structure is becoming visible.

Acquired Immunodeficiency Syndrome↗

[Screening and therapy of anal intraepithelial neoplasia (AIN) and anal carcinoma in patients with HIV-infection].

Anal intraepithelial neoplasia (AIN) is a potential precursor of invasive anal carcinoma. Introduction of highly active antiretroviral therapy (HAART) in the treatment of HIV infection substantially reduced the incidence of some diseases associated with opportunistic viral infections. However, the incidence of AIN is reported to increase and HAART seems to have only little impact on the regression or progression of AIN. Paradoxically, improvement of survival in the HAART era results in an increased risk of anal cancer. The incidence of anal carcinoma amongst homosexual men is substantially higher compared to the normal population (35/100.000). This incidence is similar to the incidence of cervical cancer before screening for CIN with cervical cytology. Recent data suggest that the incidence of AIN and anal cancer is even higher among HIV-infected individuals. Both cancer entities share biologic similarities, including the association with human papillomavirus infection (HPV). Screening for CIN with cervical cytology and early treatment has resulted in a significant decline in the incidence of cervical carcinoma. Like cervical cancer, anal carcinoma may be preventable through identification and treatment of its precursors. Future efforts should focus on a screening protocol, training of clinicians in the diagnosis and treatment of AIN and anal carcinoma, and novel approaches to treatment of these lesions. This screening protocol could help to reduce anal cancer in HIV-infection as well as save limited resources in health care system.

Antiretroviral Therapy, Highly Active↗

[HIV/AIDS Competence Network. An example for research networking in Germany].

Thanks to a nationwide network of specialized, clinic-associated outpatient facilities and competent registered physicians, the quality of care for HIV-infected patients in Germany is high. Although basic HIV research is also well advanced in several centers, in contrast Germany's clinical HIV research is barely discemable on an international level. This deficit is primarily due to a lack of clinical studies involving patients from across the country and the fact that no national patient cohort system exists which could provide a basis for such clinical studies. The competence network HIV/AIDS aims to overcome this shortcoming by serving as a comprehensive, nationwide research alliance. The established patient cohort is linked to 13 projects. The infrastructure required for communications and data exchange will be based on a telematics platform. There will also be various service facilities established within the network, creating an organizational structure to promote the horizontal exchange of information between centers, as well as establish the vertical exchange of knowledge between physicians, patients, public health policy makers, and the general public.

Academies and Institutes↗

Prevalence of endocrine dysfunction in HIV-infected men.

OBJECTIVE: Endocrine dysfunction is a common problem in patients with human immunodeficiency virus infection (HIV). We therefore evaluated the endocrine function in 31 male homosexual HIV-1-infected men: mean age 37 +/- 7.2 years (range 24-52). METHODS AND MATERIALS: Blood was obtained for baseline T3, T4, TSH, LH, FSH, prolactin, testosterone, ACTH and cortisol values. Endocrine function tests were performed as TRH, CRH, ACTH, LH-RH and HCG tests. RESULTS: Thyroid function: There was a temporarily increased TSH in 3 of 17 patients but normal levels for T3, T4 and fT4 (without thyroid antibodies). One patient showed signs of latent hyperthyroidism (no response in TRH test). Adrenocortical function: Two patients had adrenal insufficiency. They showed a normal baseline cortisol level, an elevated ACTH level and no increase in cortisol levels after stimulation with CRH. All other patients revealed normal responses on the CRH/ACTH tests. Gonadal function: 9 patients had elevated FSH levels (tubular insufficiency), 4 patients additionally had increased LH levels (hypergonadotropic hypogonadism). 5 patients showed signs of tertiary hypogonadism (low LH and testosterone, increase of LH after stimulation with LH-RH). CONCLUSION: In disorders of thyroid and adrenocortical function of primary or tertiary origin, a substitution of hormones should be taken into consideration.

Adrenal Cortex↗

Influence of foscarnet on HIV-associated Kaposi's sarcoma derived cell lines.

Recent reports showed a positive therapeutic effect of foscarnet on Kaposi's sarcoma (KS) in HIV-positive patients. We investigated the therapeutic effect of foscarnet on KS-derived cell lines. Three KS spindle cell cultures of HIV-positive patients as well three fibroblast cell cultures of HIV-positive as HIV-negative patients were established. The influence of different foscarnet concentrations (50, 100, 200, 400, 600, 1000 microg/ml) on these cell lines were analysed. There was no significant change in fibroblast cell numbers suggesting that there is neither a proliferative nor an antiproliferative effect of foscarnet on these cell lines. Furthermore, incubation of the three KS-derived cell lines of HIV-positive patients with different foscarnet concentrations did not change KS-cell number significantly.

Antiviral Agents↗

Effect of fusidic acid on the hepatic cytochrome P450 enzyme system.

OBJECTIVE: To investigate the effects of fusidic acid therapy on the hepatic cytochrome P450 (CYP450) enzyme system. METHODS: Thirty HIV-seropositive L-methadone-substituted i.v. drug abusers (stage CDC/WHO B2 - 3 with CD4+-counts ranging from 65 to 293/microl) were randomized into 3 groups (A - C). Ten patients were treated with fusidic acid 500 mg/day over a period of 14 (group A) or 28 days (group B), respectively. Patients in group C served as a control group and did not receive any medication apart from L-methadone. In order to investigate the hepatic monooxygenase system, pharmacokinetics were determined in all patients before initiation and 14 and 28 days after starting therapy with fusidic acid. The concentration of antipyrine and its 3 main metabolites (norantipyrine (NORA), 4-hydroxyantipyrine (OHA), 3-hydroxymethylantipyrine (HMA)) in plasma and urine were measured by high-performance liquid chromatography (HPLC). RESULTS: No effects on antipyrine pharmacokinetics and pharmacokinetics of antipyrine metabolites were found in group A after 14 days of fusidic acid intake and in the control group without therapy. However, in contrast an activation of the CYP450 enzyme system was observed in group B after 28 days of fusidic acid therapy with an increase of total antipyrine clearance (43.0 +/- 7.62 ml/min to 51.0 +/- 9.03 ml/min) as well as clearances to all metabolites (NORA 7.11 +/- 1.75 to 8.60 +/-2.10 ml/min, OHA 11.5 +/- 2.89 to 14.0 +/- 3.97 ml/min, HMA 4.05 +/- 0.99 to 4.94 +/- 1.27 ml/min). Antipyrine half-life was significantly reduced (12.3 +/- 2.8 h to 9.4 +/- 2.2 h) and some patients developed clinical signs of L-methadone underdosage. CONCLUSIONS: Our results suggest that fusidic acid has a time-dependent activating effect on the CYP450 enzyme system. Especially in treatment of patients who are frequently under multidrug regimens such as HIV-positive patients drug interactions should be taken into consideration.

Anti-Bacterial Agents↗

Thymic selection of H-2-incompatible bone marrow cells in SCID mice. Differences in T help for induction of B cell IgG responses versus cytotoxic T cells.

Mice with congenital severe combined immunodeficiency disease (SCID) failed to mount either a T cell-independent IgM or T cell-dependent IgG anti-vesicular stomatitis virus (VSV) Indiana (IND) response. They did not generate cytotoxic T cells against lymphocytic choriomeningitis virus (LCMV) or vaccinia virus, but exhibited NK cell-like activities. When SCID mice were given bone marrow from syngeneic BALB/c (H-2d) nu/nu mice, all immune responses were expressed at control levels. If SCID mice were reconstituted with allogeneic H-2b C57BL/6 nu/nu bone marrow, the following primary anti-viral immune responses were measured. T-independent IgM anti-VSV-IND were normal, but T-dependent IgG anti-VSV-IND responses were absent. Cytotoxic T cell responses to LCMV and vaccinia virus were within normal ranges, were donor cell mediated, and were specific exclusively for the recipient SCID H-2d type. Since antigen presentation by spleen cells was functional in these chimaeras, the presented results indicate that (a) thymic selection of T cell restriction is strict; and (b) the type of T help necessary for B cells depends upon H-2-restricted contact between T and B cells, whereas, such contact-dependent help is not mandatory for the induction of virus-specific cytotoxic T cells.

Animals↗

[Problems of standardization in electrically induced experimental thrombosis].

Electrically induced experimental thrombosis was investigated to the possibility of their standardization and reproduction and with respect with it for their qualification as model thrombosis. The lesions of the vessel wall by the electric field were recorded quantitatively by passive electrical behaviour of the arterial wall.

Animals↗

[Thrombocyte changes in electrically induced experimental thrombosis].

The influence of the function of the thrombocytes after electrical thrombosis induction by means of anodic direct current was investigated in 39 mongrel dogs. The platelet factor 3, the rotation thromboelastography, and the collagen induced thrombocytes aggregation in the optical test by Born was examined. The platelet factor 3 adhering on the thrombocytes decreased from 95% to 49% in the course of the thrombosis induction. Its activity was provable by means of the rotation thrombelastogram in the plasma. Besides of it the electrical field caused an activation of the thrombocytes which corresponds to a contact activation on foreign body surfaces. The collagen induced aggregation ability of the thrombocytes remains unaffected after the passage of the electrical field.

Animals↗

[Significance of blood flow in electrically induced thrombosis].

The thrombosis in dependence on the stream velocity in the electrically induced thrombosis was investigated by blood flow measurements in the femoral artery in 16 mongrel dogs. Thromboses were shown histologically in all 16 animals. 8 of them did not obturate. Obturating thromboses were produced with the application of anodic direct current of 1 mA during 60 minutes only with a blood stream velocity between 0.0465 and 0.0928 m/s. Not any obturating thrombosis was visible outside of this range.

Animals↗

[Vascular injuries caused by electric direct current in experimental thrombosis models].

The eventual causes of the lesion of the vascular wall through electric direct current (D. C.) in experimental artificial thrombosis are discussed by means of microscopic investigations by electron microscope and light microscope in altogether 73 mongrel dogs and 14 mini pigs. No thermic lesions of the vascular wall were observed in the coronary thrombosis pattern on the closed thorax by means of 1 mA amperage and an induction time of 60 minutes. Secondary processes for cell lesions are to be made responsible in which the electrolysis on the cell membrane and the influence of functional ranges in the artery wall play an important part.

Animals↗

[Light and electron microscopy studies on experimental arterial thrombosis in dwarf swine].

In light and electron microscopic investigations on electrically induced thrombosis in the femoral artery of the minipig thrombi by deposition of platelets were found. Thrombosis was induced by means of an intravascular electrode with constant current intensity of 1 mA and different induction periods. Injury of the vascular wall was found in every case of thrombosis, ranging from minimal lesion of endothelium to almost total necrosis of the vascular wall. Aside from direct impact by the current on the vascular wall and the blood, mechanical, rheological and hypoxemic causes can not be excluded.

Animals↗

[pH measurements in the vascular wall of dogs with electrically induced thrombosis of the femoral artery].

Electrically induced thrombosis is often used for pathophysiologic and therapeutic experiments. The pH value of the vascular wall was measured to approach the features of this thrombosis. After inducing thrombosis by direct current, pH value of the intima of femoral artery was found decreased. The anode was inserted in the lumen. As to the behavior of the pH value, electric thrombosis and clinical thrombosis are similar. Electric thrombosis therefore seems to be valuable for comparing investigations.

Animals↗