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Biomedical subjects

U Hartmann

Publications and source records attributed to U Hartmann.

At least 55 records · Page 3Linked to original sources
PubMed2000

Training and overtraining markers in selected sport events.

PURPOSE: Varieties of symptoms are supposed to detect overtraining (OT). Besides the problems of diagnosis and analysis in elite athletes, a daily monitoring of training status takes place with measurement of the parameters serum urea (SU) and serum creatine kinase (CK); therefore, their meaningfulness will be examined, with special respect inter- and intra-individually. METHODS: Data were obtained from determinations during training from athletes in rowing and athletes of international level. RESULTS: For 6981 SU determinations (male, N = 717; female, N = 285), a slightly asymmetric normal distribution was found (male, 80%, 5-7 mmol x L(-1); female, 75%, 4-6 mmol x L(-1)). Values for women were approximately 1.5 mmol x L(-1) lower. Individual variability was enormous; there seems little point in setting fixed value as 8.3 mmol x L(-1) for men and 7.0 mmol x L(-1) for women as a critical limit for OT. CK has also been measured and evaluated in sports as an essential parameter for determination of muscular stress. Frequency distributions of CK in 2790 samples (male, N = 497; female, N = 350) presented an asymmetric normal distribution with distinct trend toward higher values being evident for the range between 100 and 250 U x L(-1). Conspicuously elevated values occurred in the ranges 250-350 U x L(-1) and 1000-2000 U x L(-1). Men's maximal values were 3000 U x L(-1) and 1150 U x L(-1) for women. Individual variability was enormous. Athletes with chronically low CK exhibited mainly low variability; those with chronically higher values exhibited considerable variability. CONCLUSIONS: Establishment of both parameters should be useful to determine individual baselines from a large number of samples. Determinations should be made at least every 3 d in standardized conditions. If a large increase is observed in combination with reduced exercise tolerance after a phase of exertion (2-4 d), then the possibility of a catabolic/metabolic activity or insufficient exercise tolerance becomes much more likely.

Biomarkers↗
PubMed2000

Plasma levels of cavernous and systemic norepinephrine and epinephrine in men during different phases of penile erection.

PURPOSE: Knowledge of the functional anatomy, hemodynamics, neurophysiology and pharmacology of penile erection has improved tremendously during the last 2 decades. However, only few in vivo studies on human peripheral neurotransmission have been carried out up until now. Therefore, we conducted a study to examine plasma levels of catecholamines norepinephrine (NE) and epinephrine (E) in the peripheral and cavernous blood of healthy men during penile flaccidity and in different phases of erection. MATERIALS AND METHODS: Blood samples were drawn simultaneously from the corpus cavernosum (CC) and the cubital vein (P) in 53 healthy volunteers with normal erectile function, in four different functional states of the cavernous erectile tissue (flaccidity = 1, tumescence = 2, rigidity = 3, detumescence = 4). Penile erections were induced by audiovisual and tactile stimulation and the plasma concentrations of NE and E were determined by means of a radioimmunoassay (RIA). RESULTS: A significant (p <0.001) reduction of NE in CC plasma was found from flaccidity (362 + or - 173 pg./ml.) to rigidity (248 + or - 122 pg./ml.), followed by an increase in the detumescence phase (336 + or - 199 pg./ml.), (p <0.001). In contrast, changes in NE levels in the peripheral plasma were less pronounced from 1P (202 + or - 102 pg./ml.) to 3P (229 + or - 118 pg./ml.), (p = 0.006) and from 3P to 4P (222 + or - 127 pg./ml.), respectively (p = 0.370). The most pronounced increase in cavernous E levels were observed from flaccidity (47 + or - 41 pg. /ml.) to tumescence (130 + or - 106 pg./ml.) (p <0.001). Cavernous E levels dropped significantly from 113 + or - 67 pg./ml. during rigidity to 76 + or - 57 pg./ml. + or - during detumescence (p <0.001). The course of peripheral plasma levels of E was similar to that in the cavernous blood. Mean peripheral E level was 69 + or - 55 pg./ml. in the state of penile flaccidity, reaching 98 + or - 78 pg./ml. in tumescence and 82 + or - 64 pg./ml. in rigidity (p <0.001), respectively, and finally decreasing to 62 + or - 46 pg./ml. in detumescence. CONCLUSION: Penile erection, based on the relaxation of cavernous and arterial smooth muscle, is accompanied by a significant reduction of NE in cavernous blood, while E levels rose in peripheral and cavernous blood during developing erection.

Adult↗
PubMed2000

Possible role of human growth hormone in penile erection.

PURPOSE: Treatment with recombinant human growth hormone in adult patients with growth hormone deficiency increases nitric oxide and cyclic guanosine monophosphate (cGMP). We examined the functional in vitro effects of recombinant human growth hormone on tissue tension and cyclic nucleotide levels of human corpus cavernosum and detected changes in growth hormone in the cavernous and peripheral blood during different phases of penile erection. MATERIALS AND METHODS: Relaxant responses of human corpus cavernosum were investigated using the organ bath technique. Tissue levels of cGMP were determined by a specific radioimmunoassay after dose dependent exposition of isolated human corpus cavernosum strips to recombinant human growth hormone. In 35 healthy potent volunteers blood samples were obtained simultaneously from the corpus cavernosum and cubital vein during different functional conditions of the penis, including flaccidity, tumescence, rigidity and detumescence. Penile erection was induced by audiovisual and tactile stimulation. Serum growth hormone was determined by an immunoradiometric assay. RESULTS: Recombinant human growth hormone elicited dose dependent relaxation of human corpus cavernosum strips in vitro. The relaxing potency of recombinant human growth hormone was paralleled by its ability to elevate intracellular levels of cGMP. In vivo the peripheral growth hormone serum profile of the respective penile conditions did not significantly differ from those of cavernous serum. The main increase in growth hormone to greater than 90% was determined during developing penile tumescence, followed by a transient decrease afterward. CONCLUSIONS: These results suggest that penile erection may probably be induced by growth hormone through its cGMP stimulating activity on human corpus cavernosum smooth muscle.

Adult↗
PubMed1999

Evaluation of serological screening of cadaveric sera for donor selection for cornea transplantation.

Human corneas are explanted for grafting as late as 72 h after death, for example, from medical examiner cases. Currently, infection of the donor with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) is excluded in most cornea banks by serological testing of the cadaveric serum only. The reliability of this strategy was investigated by testing paired cadaveric and premortem sera of 33 potential donors. Results were discordant in 17 of 33 donors by at least one assay. Most frequently, HBsAg enzyme-linked immunosorbent assay (ELISA) yielded false-positive results with the cadaveric serum (16 of 33 serum pairs). Virus safety of the graft was affected in a single case, which was HCV antibody negative in the cadaveric serum, but positive in the premortem serum (confirmed by HCV-RIBA strip immunoassay). Forensic DNA profiling by polymerase chain reaction (PCR) of both serum samples confirmed that these were derived from the same individual. In conclusion, the results indicate that serological testing of cadaveric sera is not a reliable method for screening of potential cornea donors, and may not be sufficient for the virus safety of cornea grafts. Therefore, other screening strategies such as detection of viral nucleic acids by PCR should be evaluated.

Adult↗
PubMed1999

Human and porcine anterior lens capsule as support for growing and grafting retinal pigment epithelium and iris pigment epithelium.

PURPOSE: To establish a method for transplantation of cultured monolayers of RPE and IPE into the subretinal space, anterior lens capsule was evaluated for its suitability to serve as growth support and carrier for transplantation procedures. MATERIALS AND METHODS: Twenty-four anterior lens capsules were obtained from porcine eyes. The same number of human lens capsules was obtained during cataract surgery. Six lens capsules of each species were stored at -80 degrees C. Subsequently, the capsules were transferred onto type-I collagen. A second set of six lens capsules was treated identically except for the cryo treatment. A third set of six capsules was initially exposed to 0.05% trypsin for 30 min. Suspended porcine RPE and IPE cells (5 x 10(4) cells/well) were seeded on the top of each capsule. The remaining six lens capsules served as controls and were incubated in uncoated 12-well dishes without undergoing experimental treatment. The cultures were maintained in a water-saturated atmosphere at 37 degrees C with 5% CO(2). Six days later, viability, morphology, and cell density were determined. The capsules covered by a confluent monolayer of cells were transferred into uncoated wells and cultivated for another 10 days. At the end of the experiment, light and phase-contrast microscopy was performed on all capsules. RESULTS: Storage at -80 degrees C and exposure to trypsin resulted in significant reduction of cellular contamination. The highest cell density was found after 5 days when capsules which had undergone cryopreservation or trypsin exposure served as support for RPE and IPE. The pigment cell layer was firmly attached to the capsules and permitted a transfer to other culture flasks without significant cell loss. The IPE cell layer remained confluent after transfer to uncoated culture flasks, while the RPE cell layer ceased to proliferate 10 days after transfer. CONCLUSIONS: Lens capsules may be suitable for growing and supporting monolayers of pigment epithelial cells. Especially IPE cells formed stable monolayers on anterior lens capsules which could be transferred to secondary culture flasks without inflicting damage on the cells.

Animals↗
PubMed1999

Molecular cloning of testican-2: defining a novel calcium-binding proteoglycan family expressed in brain.

We have screened a human cDNA library using an expressed sequence tag related to the BM-40/secreted protein, acidic and rich in cysteine (SPARC)/osteonectin family of proteins and isolated a novel cDNA. It encodes a protein precursor of 424 amino acids that consists of a signal peptide, a follistatin-like domain, a Ca2+-binding domain, a thyroglobulin-like domain, and a C-terminal region with two putative glycosaminoglycan attachment sites. The protein is homologous to testican-1 and was termed testican-2. Testican-1 is a proteoglycan originally isolated from human seminal plasma that is also expressed in brain. Northern blot hybridization of testican-2 showed a 6.1-kb mRNA expressed mainly in CNS but also found in lung and testis. A widespread expression in multiple neuronal cell types in olfactory bulb, cerebral cortex, thalamus, hippocampus, cerebellum, and medulla was detected by in situ hybridization. A recombinant fragment consisting of the Ca2+-binding EF-hand domain and the thyroglobulin-like domain of testican-2 showed a reversible Ca2+-dependent conformational change in circular dichroism studies. Testican-1 and -2 form a novel Ca2+-binding proteoglycan family built of modular domains with the potential to participate in diverse steps of neurogenesis.

Amino Acid Sequence↗
PubMed1998

Knock-out mutants from an En-1 mutagenized Arabidopsis thaliana population generate phenylpropanoid biosynthesis phenotypes.

A collection of 8,000 Arabidopsis thaliana plants carrying 48,000 insertions of the maize transposable element En-1 has been generated. This population was used for reverse genetic analyses to identify insertions in individual gene loci. By using a PCR-based screening protocol, insertions were found in 55 genes. En-1 showed no preference for transcribed or untranscribed regions nor for a particular orientation relative to the gene of interest. In several cases, En-1 was inserted within a few kilobases upstream or downstream of the gene. En-1 was mobilized from such positions into the respective gene to cause gene disruption. Knock-out alleles of genes involved in flavonoid biosynthesis were generated. One mutant line contained an En-1 insertion in the flavonol synthase gene (FLS) and showed drastically reduced levels of kaempferol. Allelism tests with other lines containing En-1 insertions in the flavanone 3-hydroxylase gene (F3H) demonstrated that TRANSPARENT TESTA 6 (TT6) encodes flavanone 3-hydroxylase. The f3h and fls null mutants complete the set of A. thaliana lines defective in early steps of the flavonoid pathway. These experiments demonstrate the efficiency of the screening method and gene disruption strategy used for assigning functions to genes defined only by sequence.

Arabidopsis↗
PubMed1998

[Psychological stress factors in erectile dysfunctions. Causal models and empirical results].

In this paper the role of psychosocial factors in erectile dysfunction is examined in two different ways: (1) Current approaches to the causation of psychogenic erectile dysfunctions are reviewed and discussed. (2) Empirical results from a large unselected sample of sexually dysfunctional men are presented and compared to a sample of functional men. Concerning etiological models the traditional unidimensional dichotomous concepts (psychogenic versus organic) of erectile dysfunction have to be abandoned and replaced by two-dimensional models that are able to take the clinical reality into account that many patients have both significant psychological and organic factors in their disorder. The main causes of psychogenic erectile disorders can be divided into three groups, each belonging to a different phase of time: (i) immediate factors (performance anxiety), (ii) antecedent life events from recent history, (iii) developmental vulnerabilities from childhood and adolescence. The specific interplay as well as the importance of the different groups is different in primary and secondary erectile disorders. The empirical results presented here are based on a sample of 751 patients from our interdisciplinary outpatient unit for sexually dysfunctional men and a group of 55 sexually functional men. Both groups completed a self-developed, multidimensional questionnaire addressing a variety of psychosocial and descriptive factors concerning erectile disorders. The results prove the heterogeneity of patients and their respective erectile problems and show a number of highly significant group differences. The frequent comorbidity of erectile disorders and premature ejaculation and disorders of desire is worth mentioning as well as the high prevalence of depression and the extreme extent of performance anxiety in the patient group. The results are discussed with respect to future treatment strategies. The necessity of combined psychosomatic approaches optimizing the efficacy of all available therapeutic options is particularly stressed.

Adolescent↗
PubMed1998

Neuroendocrine and cardiovascular response to sexual arousal and orgasm in men.

Data regarding the neuroendocrine response pattern to sexual arousal and orgasm in man are inconsistent. In this study, ten healthy male volunteers were continuously monitored for their cardiovascular and neuroendocrine response to sexual arousal and orgasm. Blood was continuously drawn before, during and after masturbation-induced orgasm and analyzed for plasma concentrations of adrenaline, noradrenaline, cortisol, luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, growth hormone (GH), beta-endorphin and testosterone. Orgasm induced transient increases in heart rate, blood pressure and noradrenaline plasma levels. Prolactin plasma levels increased during orgasm and remained elevated 30 min after orgasm. In contrast, none of the other endocrine variables were significantly affected by sexual arousal and orgasm.

Adult↗
PubMed1998

Identification of UV/blue light-response elements in the Arabidopsis thaliana chalcone synthase promoter using a homologous protoplast transient expression system.

To identify DNA sequences of the Arabidopsis thaliana chalcone synthase gene (CHS) concerned with induction by UV-B and UV-A/blue light, AtCHS promoter constructions were assayed by transient expression in protoplasts prepared from two different lines of cultured A. thaliana cells. The protoplasts responded similarly to A. thaliana leaf tissue in light-dependent CHS transcript accumulation. The reporter enzyme beta-glucuronidase (GUS) was used to monitor light-responsive promoter activity. A 1972 bp promoter conferred UV-B and UV-A/blue light induction of GUS activity. Deletion to 164 bp resulted in reduced promoter strength but retention of responsiveness to UV-B and UV-A/blue light. Further deletion abolished transcriptional activity. The 164 bp promoter contains sequences closely resembling LRUPcCHS, (light-responsive unit of the Petroselinum crispum CHS promoter). This A. thaliana CHS promoter region, designated LRUAtCHS, was sufficient to confer UV-B and UV-A/blue light responsiveness to a heterologous core promoter. Mutation of sequences in LRUAtCHS corresponding to the ACGT element and the MYB recognition element of LRUPcCHS resulted in inactivation of the 164 bp and 335 bp promoter deletions. However, the mutant 668 bp promoter retained residual UV-B and UV-A/blue light-induced expression, indicating the presence of additional functional sequences upstream of -335. Mutation of a single G-box-like sequence around -442 had no effect on light responsiveness, indicating that it does not function in light regulation of this promoter. Since no difference in responsiveness to UV-B and UV-A/blue light was observed with any promoter variant, we conclude that the two phototransduction pathways regulate transcription factors which interact with common promoter elements. The results from-our analysis of a A. thaliana light-responsive promoter will facilitate the study of light-dependent gene regulation by genetic means in Arabidopsis thaliana.

Acyltransferases↗
PubMed1998

[Standards for treatment and expert opinion on transsexuals. The German Society for Sexual Research, The Academy of Sexual medicine and the Society for Sexual Science].

Over the last two-and-a-half years a committee of experts, consisting of members of the three leading German sexology associations, developed guidelines for treating and assessing transsexuals. Their purpose is to improve the care for patients with sex identity disorders and to ensure that such care is of uniform quality to avoid erroneous decisions to the disadvantage of those affected. The guidelines are set out in full.

Diagnosis, Differential↗
PubMed1998

The neural cell adhesion molecule is a receptor for rabies virus.

Previous reports strongly suggest that, in addition to the nicotinic acetylcholine receptor, rabies virus can use other, as-yet-unidentified receptors. We found that laboratory cell lines susceptible to rabies virus infection express the neural cell adhesion molecule (NCAM) (CD56) on their surface, whereas resistant cells do not, supporting the idea that NCAM could be a rabies virus receptor. We observed that (i) incubation with rabies virus decreases the surface expression of NCAM; (ii) treatment of susceptible cells with heparan sulfate, a ligand for NCAM, or with NCAM antibodies significantly reduces the rabies virus infection; and (iii) preincubation of rabies virus inoculum with soluble NCAM protein as a receptor decoy drastically neutralizes the capacity of rabies virus to infect susceptible cells. Moreover, we demonstrated that transfection of resistant L fibroblasts with the NCAM-encoding gene induces rabies virus susceptibility whereas absence of NCAM in the primary cortical cell cultures prepared from NCAM-deficient mice reduces the rabies virus infection and virus production. This provides evidence that NCAM is an in vitro receptor for the rabies virus. Moreover, the in vivo relevance for the use of NCAM as a receptor was demonstrated by the infection of NCAM-deficient mice, in which rabies mortality was delayed and brain invasion by rabies virus was drastically restricted. Our results showed that NCAM, which is expressed mainly in the adult nervous system, plays an important role in rabies infection. However, it cannot be excluded that receptors other than NCAM are utilized. Thus, the description of NCAM as a new rabies virus receptor would be another example of the use by viruses of more than one receptor to gain entry into the host.

Animals↗
PubMed1998

Oral phentolamine as treatment for erectile dysfunction.

PURPOSE: For most patients with erectile dysfunction oral agents are a preferred treatment option. Oral or buccal phentolamine has been shown to produce full erections in impotent subsets of study populations. We evaluate the efficacy of oral phentolamine. MATERIALS AND METHODS: After a comprehensive evaluation 44 patients with recent onset (less than 3 years) of erectile dysfunction and a high likelihood of organogenic etiology underwent a prospective, double-blind and placebo controlled trial with oral phentolamine after placebo. RESULTS: After placebo 4 of the 44 patients who reported full erections were excluded from study. Of the 40 patients in the double-blind phase full erections were achieved by 2 of 10 with placebo, and 3 of 10 with 20 mg., 5 of 10 with 40 mg. and 4 of 10 with 60 mg. phentolamine. There were no serious complications observed during the study, and only a single minor side effect occurred in 1 patient after 60 mg. phentolamine. CONCLUSIONS: Our results indicate that oral phentolamine may be of benefit for the treatment of erectile dysfunction. Further studies are required to corroborate our findings.

Administration, Oral↗
PubMed1998

[Erectile dysfunction: psychological causes, diagnosis and therapy].

For clinical practice, erectile dysfunction is the most important form of male sexual disorders. In the majority of patients causation and course of their erectile disorder is determined by a close interplay of somatic and psychosocial factors. This psychosomatic interaction has to be taken into account during diagnostic assessment and therapy. The old dichotomous concepts (psychogenic versus organic) of erectile dysfunction have to be replaced by multidimensional models that include dispositonal as well as chronifying factors. The main causes of psychogenic erectile disorders can be divided into three groups, each belonging to a different phase of time: 1. immediate factors (performance anxiety), 2. antecedent life events from recent history, 3. developmental vulnerabilities from childhood and adolescence. The most important instrument for the psychological evaluation of sexually dysfunctional patients is a comprehensive sexual history in which partner related aspects should be particularly focused. In treating psychogenic erectile dysfunctions sex therapy is a reliable and efficient treatment option with a reasonably good long-term prognosis. In future, sex therapy should be combined with somatic treatment options to reach a truly integrative approach to this complex disorder.

Adolescent↗
PubMed1997

Carrier-independent hapten recognition and promiscuous MHC restriction by CD4 T cells induced by trinitrophenylated peptides.

The elucidation of mechanisms underlying the recognition of haptens by class II MHC-restricted T cells is instrumental for the understanding of chemical- and drug-induced allergies. We have previously demonstrated that trinitrophenyl (TNP) peptides represent dominant antigenic epitopes for CD8+ and CD4+ mouse T cells triggered by chemically TNP-modified APC. Here, we report the characterization of TNP-specific, CD4+ mouse T cell lines and hybridomas that were induced in vivo and in vitro by defined hapten-conjugated peptides. These peptides, which we had previously shown to induce contact sensitivity to picryl chloride in vivo regardless of sequence homologies to mouse proteins, were found to activate carrier-independent TNP-specific T cells in vitro. We interpret these findings to support our view that carrier-independent T cells, reactive to particularly repetitive hapten epitopes, may play a crucial role in allergies to chemicals and drugs. In addition to carrier independence, one of our hybridomas (IT-H6/A11) exhibited a striking promiscuity of MHC restriction. Although absolutely dependent in its TNP reactivity on the presence of MHC class II molecules, the IT H6/A11 hybridoma completely ignored class II polymorphism and even reacted to TNP peptides presented on human DR molecules. Regarding hapten allergies in humans with a heterozygous situation for three types of class II molecules (DR, DP, and DQ), such promiscuous MHC restriction should lead to the presentation of even higher epitope densities to the respective T cell clones. Hybridoma IT-H6/A11, reacting to TNP independent of carrier peptide and of MHC haplotype, also allowed for an unusually systematic study of the minimal requirements for TNP recognition. Despite an almost complete ignorance of amino acid side chains on the carrier peptide, our data indicate a clearly position-specific interaction of hapten and TCR.

Animals↗
PubMed1997

Psychological subtypes of erectile dysfunction: results of statistically analyses and clinical practice.

In contrast to the impressive advances made in somatic research of erectile dysfunction (ED), psychogenic ED is mostly treated as a monolithic block or is merely defined by exclusion of organic factors. This paper proceeds from the assumption that a classification of psychological subtypes of ED is urgently needed and has to include a categorization of different pathogenetic mechanisms as well as a classification of interaction patterns with somatic risk factors. After a brief review of current approaches, psychological subtypes of ED are examined along two different lines of evidence. First, 236 consecutive patients from an ED outpatient. unit were included in a cluster analysis to identify homogeneous subgroups of cases. Three clusters emerged, whose main characteristics as well as most important discriminating variables were further explored by various statistical procedures. Second, on the basis of clinical experience a four-level model of psychogenic ED is proposed that consists of dispositional, etiologic, pathogenetic, and maintaining factors. In addition, four different pathogenetic modes of psychogenic ED are differentiated, which have been labeled actual-neurotic, psychoneurotic, psychosomatic, and functional. Conclusions concentrate on these modes as well as on the empirical subtypes and their implications for clinical practice and future research. Our results indicate that we are just beginning to understand the complex pathogenic interface between psychological factors and manifest ED.

Erectile Dysfunction↗
PubMed1997

[Psychiatric evaluation in accordance with the transsexualism regulation. An experience-based plea for guidelines and against arbitrary bias].

Today patients want to change their Christian names not so much for social support but in order to obtain sex change operations. For this reason among others we caution against casual and careless evaluations and plead for conscientiousness and thoroughness. The spectrum of 16 evaluation cases in the year 1995 is presented. Following this and looking for guiding principles, the most important aspects are discussed: the dilatable frame of the written law, the examiner's diagnostic process, the duty of being well informed, reconstruction of development as the first goal of examination, real-life self-testing and therapy, the obligation to report one's own findings, change of Christian name and indication of operation, evaluation for gender changing, problems of the judge-expert relationship and of future development.

Adolescent↗