Biomedical subjects

K Mann

Publications and source records attributed to K Mann.

At least 253 records · Page 14Linked to original sources

PubMed1996

Effects of pulsed high-frequency electromagnetic fields on human sleep.

In the present study we investigated the influence of pulsed high-frequency electromagnetic fields of digital mobile radio telephones on sleep in healthy humans. Besides a hypnotic effect with shortening of sleep onset latency, a REM suppressive effect with reduction of duration and percentage of REM sleep was found. Moreover, spectral analysis revealed qualitative alterations of the EEG signal during REM sleep with an increased spectral power density. Knowing the relevance of REM sleep for adequate information processing in the brain, especially concerning mnestic functions and learning processes, the results emphasize the necessity to carry out further investigations on the interaction of this type of electromagnetic fields and the human organism.

Adult↗

PubMed1996

Human chorionic gonadotropin-beta in the differentiation of malignancy-related and nonmalignant ascites.

The clinical value of the tumor marker human chorionic gonadotropin-beta (hCG-beta) in ascitic fluid for the differentiation of malignancy-related and non-malignant ascites was evaluated. Ascitic fluid protein, cholesterol and cytological examination were determined for comparison. Thirty-six patients with malignancy-related ascites (27 peritoneal carcinomatosis, 9 miscellaneous malignant causes without peritoneal carcinomatosis) and 69 patients with nonmalignant ascites (55 with liver cirrhosis, 14 with miscellaneous nonmalignant causes) were investigated. hCG-beta concentrations were elevated in malignant samples and with a cut-off value of 10 mIU/ml hCG-beta yielded a sensitivity of 61%, specificity of 94% and efficiency of 83%. Ascitic fluid protein (cut-off value 3.0 g/100 ml) and cholesterol (cut-off value 45 mg/100 ml) concentrations showed a sensitivity of 64%/83%, specificity of 77%/81% and efficiency of 72%/82%. The combination of hCG-beta and cytological examination yielded 89.5% differential diagnostic efficiency, superior to the combinations of protein and cytology or protein and hCG-beta. hCG-beta tended to be superior to protein/cholesterol determination regarding sensitivity (44% vs. 11%/33%) and specificity (79% vs. 50%/57%) in the subgroups of patients with miscellaneous causes of ascites. In conclusion, hCG-beta is frequently elevated in malignancy-related ascites and seems to be as useful a parameter as total protein for the differentiation of malignancy-related from nonmalignant ascites.

Ascites↗

PubMed1996

Mutations of the ret protooncogene in German multiple endocrine neoplasia families: relation between genotype and phenotype. German Medullary Thyroid Carcinoma Study Group.

It has been suggested that not only the position but also the nature of the mutations of the ret protooncogene strongly correlate with the clinical manifestation of the multiple endocrine neoplasm type 2 (MEN 2) syndrome. In particular, individuals with a Cys634-Arg substitution should have a greater risk of developing parathyroid disease. We, therefore, analyzed 94 unrelated families from Germany with inherited medullary thyroid carcinoma (MTC) for mutation of the ret protooncogene. In all but 1 of 59 families with MEN 2A, germline mutations in the extracellular domain of the ret protein were found. Some 81% of the MEN 2A mutations affected codon 634. Phenotype-genotype correlations suggested that the prevalence of pheochromocytoma and hyperparathyroidism is significantly higher in families with codon 634 mutations, but there was no correlation with the nature of the mutation. In all but 1 of 27 familial MTC (FMTC) families, mutations were detected in 1 of 4 cysteines in the extracellular domain of the ret protooncogene. Half of the FMTC mutations affected codon 634. Mutations outside of codon 634 occurred more often in FMTC families than in MEN 2A families. In all but 1 of 8 MEN 2B patients, de novo mutations in codon 918 were found. These data confirm the preferential localization of MEN 2-associated mutations and the correlation between disease phenotype and the position of the ret mutation, but there was no correlation between the occurrence of hyperparathyroidism or pheochromocytoma and the nature of the mutation.

Amino Acid Sequence↗

PubMed1996

The pharmacological treatment of alcohol dependence: needs and possibilities.

Standard treatment for alcohol abuse may include pharmacotherapy to alleviate withdrawal symptoms followed by psychotherapy in inpatient and/or outpatient settings. Treatment goals include abstinence and reduced alcohol consumption. Standard treatment for alcoholism has a high rate of success in Germany; however, for various reasons, only a small percentage of alcoholic patients are admitted to alcoholism treatment programmes. A new drug, acamprosate, could benefit many more alcoholic patients. Several studies indicate that acamprosate reduces the craving for alcohol and enhances abstinence. Acamprosate's effect is dose-dependent and it has a few minor side-effects. In addition, the availability of acamprosate may enable family practitioners to play an increasingly important role in the treatment of alcoholic patients, thus allowing more patients to receive treatment.

Acamprosate↗

PubMed1996

Disulfide bonds and free SH-group in pig kidney aminopeptidase P.

Pig kidney aminopeptidase P contains five cysteines. In the present report four of them are shown to be involved in disulfide bridges connecting Cys9 to Cys100 and Cys267 to Cys272. The fifth cysteine, Cys58, could be carboxymethylated in the complete protein under denaturing conditions but without reduction indicating that the SH-group was free.

Aminopeptidases↗

PubMed1996

[Sequential analysis of transmission properties of the CNS during consecutive REM periods].

Auditory and visual evoked potentials during sleep were recorded in healthy subjects. After averaging of the evoked potentials separately for the different REM episodes, the corresponding so-called amplitude-frequency-characteristic was calculated. This function describes the transfer properties of the system in the frequency domain. Regarding the visual evoked potentials, no difference between consecutive REM episodes could be proven. Under auditory stimulation, a significant difference between the first and the following REM episodes was found in the beta frequency range (12.5 to 20 Hz). This indicates different mechanisms of information processing during consecutive REM episodes.

Adult↗

PubMed1996

[REM suppression induced by digital mobile radio telephones].

In the present study we investigated the effects of pulsed high-frequency electromagnetic fields irradiated by digital mobile radio telephones on sleep in healthy humans. Besides a hypnotic effect with shortening of sleep onset latency, a REM suppressive effect with reduction of duration and percentage of REM sleep was found under exposure to the field. Moreover, spectral analysis revealed an increased spectral power density of the EEG signal during REM sleep, especially in the alpha frequency band. These results emphasise the necessity to carry out further investigations on the interaction of this type of electromagnetic fields and the human organism.

Adult↗

PubMed1996

[Is the new guardianship law regarding alcoholic patients therapeutically useful? A case example].

Although treatment outcome in alcoholism is good and well documented, many patients are not sufficiently motivated for participating in a treatment program. The following case-report illustrates the example of a young male alcoholic suffering from decompensated liver cirrhoses without motivation for a long-term treatment. The positive effects of the new guidelines of the laws regulating custody and civil commitment are shown and discussed.

Adult↗

PubMed1996

Association between eye and hand dominance and hitting, fielding and pitching skill among players of the Southern Baseball League.

BACKGROUND: The relationship between eye dominance and batting skill in baseball has been investigated, but conflicting results have been obtained. In addition, little attention has been given to the relationship, if any, between eye dominance and fielding and pitching skill. METHODS: A vision screening of 215 professional baseball players in the Southern Baseball League was performed and the eye dominance of these players was determined by a sighting test. Handedness for batting, fielding, and pitching was determined by history. RESULTS: The screening revealed that 66 percent of players were right-eye dominant and that, of 92 players who met the criteria established to qualify for the league batting championship, 60 percent had matched dominance of eye and hand. When official league batting averages were obtained for these 92 players, it was found that there was no statistically significant difference between batters with matched dominance (.278 mean batting average). For the 149 fielders in the league, no statistically significant differences based on eye dominance were found for fielding average (.893 matched dominance, .864 crossed dominance); for the 89 pitchers, a similar result was obtained. Pitchers were also evaluated with respect to eye dominance and earned run average, but no significant difference was found (3.91 matched dominance, 4.03 crossed dominance). CONCLUSIONS: Results indicate that there is no association between eye dominance, and hitting, fielding, or pitching skill in baseball.

Baseball↗

PubMed1996

Does serum tumor marker half-life complement pretreatment risk stratification in metastatic nonseminomatous germ cell tumors?

The goal of this study was to determine whether the serum tumor marker half-life (MHL) of human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) during initial chemotherapy can complement pretreatment risk stratification in metastatic nonseminomatous germ cell tumors. One hundred forty-seven patients were assessable for MHL during the first two cycles of platinum-based chemotherapy. MHL calculation was based on two consecutive values using Kohn's apparent half-life formula (MHL =ln 1/2/G, where G was the gradient of the marker slope) or on three (or more) values using simple linear regression. MHL was regarded as prolonged if it was more than 3.5 days for HCG or more than 7 days for AFP. The median MHL for HCG was 2.8 days (range, 0.7-16.7) and for AFP was 6.2 days (range, 2. 6-65.4). Thirty-five of 108 patients (32%) had a prolonged MHL for HCG, 41 of 114 (36%) had a prolonged MHL for AFP, and in 59 of 147 patients (40%), either or both MHLs were prolonged. If patients with both MHLs normal were compared against patients with either or both MHLs prolonged, highly significant differences in progression-free survival (P < 0.0001) and overall survival (P = 0.0005) were demonstrated. The test accuracy was 70% for both progression-free and overall survival, and it was slightly greater than the overall predictive value of the Medical Research Council prognostic classification. A combination of Medical Research Council criteria and MHL analysis allowed us to refine prognostic assessment. Because MHL analysis is able to complement pretreatment risk stratification and can support selection of patients for early-dose intensified chemotherapy, it should be included in prospective clinical trials for patients with poor-prognosis disease.

Adolescent↗

PubMed1996

The pharmacological treatment of alcohol dependence: needs and possibilities.

Acamprosate↗

PubMed1995

Two adjacent N-terminal glutamines of BM-40 (osteonectin, SPARC) act as amine acceptor sites in transglutaminaseC-catalyzed modification.

The extracellular matrix protein BM-40 (osteonectin, SPARC) has recently been shown to be a major target for transglutaminase-catalyzed cross-linking in differentiating cartilage. In the present study we demonstrate that recombinant human BM-40 can be modified with [3H]putrescine in a 1:1 molar ratio by transglutaminaseC (tissue transglutaminase). Residues Gln3 and Gln4 were identified as major amine acceptor sites. This was confirmed with several mutant proteins, including deletions in the N-terminal domain I of BM-40, site-directed mutagenesis of the reactive glutamines, and fusion of the seven-amino acid-long N-terminal sequence (APQQEAL) to an unrelated protein. The results showed that the N-terminal target site is sufficient for modification by transglutaminase but at a low level. For high efficiency amine incorporation an intact domain I is required. The conservation of at least one of the transglutaminase target glutamines in the known vertebrate BM-40 sequences and their absence in an invertebrate homologue point to an important, but yet unknown, role of this modification in vertebrates.

Amino Acid Sequence↗

PubMed1995

Amino acid sequence of HSP-1, a major protein of stallion seminal plasma: effect of glycosylation on its heparin- and gelatin-binding capabilities.

We report the complete amino acid sequence of HSP-1, a major protein isolated from stallion seminal plasma or acid extracts of ejaculated spermatozoa. The protein consists of 121 amino acids organized in two types of homologous repeats arranged in the pattern AA'BB'. Each of the 13-15-residue A-type repeats contains two O-linked oligosaccharide chains. The B-type repeats span 44-47 amino acids each, are not glycosylated, and have the consensus pattern of the gelatin-binding fibronectin type-II module. This domain also occurs in the major bovine seminal plasma heparin-binding proteins PDC-109 (BSP-A1/A2) and BSP-A3. However, unlike the bovine proteins which bind quantitatively to a heparin-Sepharose column, stallion HSP-1 was recovered in both the flow-through and the heparin-bound fractions. Structural analysis showed that the two HSP-1 forms contain identical polypeptide chains which are differently glycosylated. Moreover, size-exclusion chromatography showed that heparin-bound HSP-1 associates with HSP-2, another major seminal plasma protein, into a 90 kDa product, whereas the non-heparin-bound glycoform of HSP-1 is eluted as a monomeric (14 kDa) protein. This suggests that glycosylation may have an indirect effect on the heparin-binding ability of HSP-1 through modulation of its aggregation state. On the other hand, both glycoforms of HSP-1 displayed gelatin-binding activity, indicating that the molecular determinants for binding heparin and gelatin are different.

Amino Acid Sequence↗

PubMed1995

Structural properties of recombinant domain III-3 of perlecan containing a globular domain inserted into an epidermal-growth-factor-like motif.

A fragment comprising approximately domain III-3 of the basement membrane heparan sulfate proteoglycan perlecan was prepared in recombinant form from kidney cell clones. This fragment was predicted to contain a cysteine-free globular domain inserted within an epidermal-growth-factor(EGF)-like motif (L4 module) and three additional EGF-like motifs (LE module) without large inserts. This prediction was confirmed by electron microscopy, which demonstrated a globule joined to a very short rod-like segment. The globule was selectively destroyed by pepsin, which also demonstrated that its insertion into an EGF-like motif did not prevent the typical disulfide connections known for such motifs. Yet the globule was more stable against neutral proteinases. The fragment showed a distinct content (55-60%) of alpha helical and beta structure and a partially reversible melting of the conformation in 6 M guanidine. Antibodies raised against recombinant domain III-3 demonstrated a complete cross-reaction with tissue-derived perlecan but not with laminin and a distinct basement membrane staining of tissue sections. Most of the epitopes were lost after reduction and alkylation. Together the data demonstrated a proper folding of recombinant domain III-3 similar to its structure in the native protein and provided the first structural evidence for a novel globular protein motif L4 based on an EGF-like scaffold.

Amino Acid Sequence↗

PubMed1995

Boar spermadhesin PSP-II: location of posttranslational modifications, heterodimer formation with PSP-I glycoforms and effect of dimerization on the ligand-binding capabilities of the subunits.

Spermadhesin PSP-II was isolated from the non-heparin-binding fraction of boar seminal plasma; its disulphide bridge pattern, and the location of a single N-glycosylation site were established. PSP-II forms a heterodimer with specific N-glycoforms of PSP-I. Although both subunits possess heparin-binding capability, the PSP-I/PSP-II complex does not. The heterodimer contains binding sites for zona pellucida glycoproteins and soybean trypsin inhibitor located in the PSP-II subunit. However, the PSP-I/PSP-II heterodimer binds only loosely to the sperm surface and is easily removed during in vitro capacitation, suggesting that the zona pellucida binding activity may not be relevant for gamete interaction. Our results show that dimerization of spermadhesins PSP-I and PSP-II markedly affects their binding capabilities.

Amino Acid Sequence↗

PubMed1995

Purification and amino acid sequence of aminopeptidase P from pig kidney.

Aminopeptidase P from kidney cortex was purified in high yield (recovery greater than or equal to 20%) by a series of column chromatographic steps after solubilization of the membrane-bound glycoprotein with n-butanol. A coupled enzymic assay, using Gly-Pro-Pro-NH-Nap as substrate and dipeptidyl-peptidase IV as auxilliary enzyme, was used to monitor the purification. The purification procedure yielded two forms of aminopeptidase P differing in their carbohydrate composition (glycoforms). Both enzyme preparations were homogeneous as assessed by SDS/PAGE silver staining, and isoelectric focusing. Both forms possessed the same substrate specificity, catalysed the same reaction, and consisted of identical protein chains. The amino acid sequence determined by Edman degradation and mass spectrometry consisted of 623 amino acids. Six N-glycosylation sites, all contained in the N-terminal half of the protein, were characterized.

Amino Acid Sequence↗

PubMed1995

Structural comparison of cuticle and interstitial collagens from annelids living in shallow sea-water and at deep-sea hydrothermal vents.

Two types of annelid collagens of different sizes were purified, one from acetic acid extracts of the cuticle (length 2.5 microns) and the other, after pepsin digestion, from interstitial spaces of the body wall (0.3 micron). They were obtained from Alvinella pompejana, Alvinella caudata and Paralvinella grasslei collected at 2600 m depth around anoxic hydrothermal vents and from Arenicola marina and Nereis diversicolor living in shallow sea-water habitats. The length of the corresponding collagens from different species and their amino acid compositions including the hydroxylation of proline were remarkably similar. The melting point of the triple helix, however, differed between the Alvinella species (approximately 45 degrees C), Paralvinella (approximately 35 degrees C) and the shallow sea-water annelids (approximately 28 degrees C), indicating adaption to habitats with different temperatures. The cuticle collagens of the annelids possess a globular domain, which is apparently involved in oligomer formation, and show similar fragment pattern. Almost identical cross-striation patterns of segment-long-spacing segments of the interstitial collagens indicated sequence similarity, which was confirmed by partial Edman degradation of alpha-chains. These data showed almost complete identity between the two Alvinella species and a lower sequence identity with Paralvinella (approximately 95%), Arenicola (67 to 72%) and the vent vestimentiferan Riftia pachyptila (64 to 71%). The data suggest a close evolutionary relationship between these worms, despite a clear separation of habitat preference and thermal stability of the collagens.

Amino Acid Sequence↗

PubMed1995

Recombinant analysis of human alpha 1 (XVI) collagen. Evidence for processing of the N-terminal globular domain.

The N-terminal non-collagenous domain NC11 of the human collagen alpha 1 (XVI) chain was obtained as a recombinant 35-kDa protein from stably transfected kidney cell clones. This form had undergone proteolytic trimming at a basic cleavage motif indicating a similar release in vivo. Domain NC11 showed a globular shape after rotary shadowing and was resistant to neutral proteases. Specific antibodies could be raised against recombinant NC11 and were used for the analysis of other cell clones transfected with the full-length alpha 1 (XVI) chain. Immunoprecipitation of detergent extracts of metabolically labelled cells demonstrated the presence of disulfide-bonded 200-kDa polypeptides possessing NC11 epitopes. This material was partially resistant to pepsin, indicating the formation of alpha 1 (XVI) chain homotrimers with a triple-helical conformation. Yet a substantial proportion of these homotrimers was degraded to fragments of variable size (35-150 kDa) when secreted into the culture medium. Several of these fragments could be obtained on a semi-preparative scale from cells grown in hollow fiber cassettes and showed substantial hydroxylation of proline, consistent with triple-helix formation. Edman degradation demonstrated the origin of some from the N-terminal and of one from a more C-terminal position of collagen XVI. This extensive degradation may be explained by the release of NC11 and by further cleavages within some of the nine interruptions of the triple-helical domain of the alpha 1(XVI) chain. Whether this process also occurs in situ remains to be shown.

Amino Acid Sequence↗