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K Seifert

Publications and source records attributed to K Seifert.

At least 19 recordsLinked to original sources
PubMed2006

Optimization of activation conditions of Rhodobacter sphaeroides in hydrogen generation process.

AIMS: To examine the effects of the culture age, illuminance intensity and changes in these parameters during activation on hydrogen generation process carried out by purple nonsulfur Rhodobacter sphaeroides bacteria. METHODS AND RESULTS: The following parameters were determined in all experiments: the amount of hydrogen evolved (measured using gas chromatography), biomass increase as dry mass, pH values and consumption of organic substance as chemical oxygen demand (COD). The medium used in the process of activation and hydrogen generation contained malic acid (15 mmol) and sodium glutamate (2 mmol). The optimum age of bacteria was 12-24 h and the best intensity of illuminance was found to be 5 cd sr m-2 on activation and 9 cd sr m-2 on hydrogen generation. These conditions provided hydrogen evolution of 1.39 l l-1 of the medium with the highest specific hydrogen production of 0.146 l H2 l-1 medium h-1 g-1 inoculum. An increase in the illuminance intensity resulted in a slight inhibition of the process. CONCLUSIONS: The activation stage of bacteria has a significant effect on the parameters of hydrogen photogeneration. The optimization of the activation stages allowed a shortening of the time of hydrogen generation and of the period after which hydrogen evolution starts. SIGNIFICANCE AND IMPACT OF THE STUDY: An innovative method of bacteria activation before the initiation of the hydrogen generation process has been used to optimize this process. The shortening of the process duration as well as the twice higher hydrogen yield can help in the designing of other systems (including also those operating under solar irradiation) in which R. sphaeroides bacteria are to be applied.

Biomass↗
PubMed2006

Nursery pollination by a moth in Silene latifolia: the role of odours in eliciting antennal and behavioural responses.

Since the 1970s it has been known that the nursery pollinator Hadena bicruris is attracted to the flowers of its most important host plant, Silene latifolia, by their scent. Here we identified important compounds for attraction of this noctuid moth. Gas chromatographic and electroantennographic methods were used to detect compounds eliciting signals in the antennae of the moth. Electrophysiologically active compounds were tested in wind-tunnel bioassays to foraging naïve moths, and the attractivity of these compounds was compared with that to the natural scent of whole S. latifolia flowers. The antennae of moths detected substances of several classes. Phenylacetaldehyde elicited the strongest signals in the antennae, but lilac aldehydes were the most attractive compounds in wind-tunnel bioassays and attracted 90% of the moths tested, as did the scent of single flowers. Our results show that the most common and abundant floral scent compounds in S. latifolia, lilac aldehydes, attracted most of the moths tested, indicating a specific adaptation of H. bicruris to its host plant.

Animals↗
PubMed2005

[Tinnitus from the point of view of an ENT practitioner].

Tinnitus lasting for more than 3 months is considered chronic. It is not a self-contained illness as such, but a symptom of a central information processing malfunction with individually distinguishing emotional reactions. However, it can, as chronically decompensated tinnitus, manifest itself as an ailment which is more or less pronounced in the person afflicted, and it can also, as a subjective sensation, be the symptom of an objective illness which must be excluded by differential diagnosis. In the majority of cases of chronic tinnitus, psychological components play a substantial role and must be taken into account in diagnosis. As a rule, no therapeutic impact can be made on chronic tinnitus. The doctor's target is therefore to achieve and stabilise habituation in the person afflicted so that, although the tinnitus will continue to exist, it will no longer be perceived as burdensome. Amongst the causes or contributory factors of tinnitus are dysfunctions of the upper cervical vertebral column and/or of the mandibular joints. In cases of tinnitus, these should always be diagnostically clarified and, wherever possible, eliminated to make habituation easier and to diminish the likelihood of recidivism.

Chronic Disease↗
PubMed2005

[Cervicogenic head and neck pain].

It is discussed controversially whether cervicogenic pain in the head and/or neck is a pathogenic entity. The good results obtained with manual therapy in patients with head and neck pain contradict the refusal of the majority of the neurologists to accept the diagnosis "cervicogenic headache." Complaints about headache are frequently encountered in the general ENT clinic. In many cases, the diagnosis of the different types of headaches can be based on the anamnesis. It is difficult to define a tension headache, because it is not a sharply defined syndrome and the disturbance of the neck represents only one of many factors. The versatile picture of the cervicogenic headache is caused by the complex neural connections in the region of the upper cervical spine. The differential diagnosis of the cervicogenic headache is described.

Headache↗
PubMed2005

[The first hearing aid increases mental capacity. Open controlled clinical trial as a pilot study].

BACKGROUND: According to the scientific literature, a hearing impairment which is acquired late reduces mental efficiency. OBJECTIVE: To determine by empirical examination whether hearing aids increase mental efficiency. PERSONS AND METHODS: An open controlled application study was carried out on the capacity of working memory in 15 first users of hearing aids. RESULTS: The working memory's capacity in the 15 users (age: 72+/-12 years; six females; crystallized IQ: 100+/-13; test-retest period: 74+/-35 days) increased 13+/-19% (IQ-increment 3.4+/-6.3 points), while the capacity of the 15 controls (age: 71+/-11 years; seven females; crystallized IQ: 103+/-12; test-retest period: 58+/-21 days) remained unchanged: 0+/-12% (IQ-change: -0.3+/-5.1 points). The difference between the samples is significant (p=0.012 one-tailed). The visually and auditively administered subtests yielded equal changes. According to self-reports, the daily wearing time was 6.7+/-3.5 h. Daily wearing times of the hearing aids (self-reports) of between 4-8 h showed the multiple IQ-gain compared to lesser or longer times. The audiometric gain in hearing without noise on the right (rho=0.58; significant), left (0.48; not significant), and on both sides (0.68; significant) correlated with IQ-gain. CONCLUSIONS: Under a more favourable usage a still more striking benefit is to be expected in mental efficiency.

Aged↗
PubMed2003

[Does hearing loss in adults diminish intelligence?].

BACKGROUND AND OBJECTIVE: Mean curves of the age course of intelligence drop shortly after early adulthood. This is particularly true of fluid intelligence, which corresponds to the immediate management of information. Less affected is crystallized intelligence, i.e. acquired knowledge. Overviews indicate that visual impairment such as cataracts explain a large portion of this intelligence loss, and that the restitution of visual capacity conspicuously increases fluid intelligence. The question also arises as to whether hearing loss acquired in adulthood can cause a similar loss in mental efficiency. METHODS: This question was investigated by reviewing the relevant literature. RESULTS: Several studies were found involving aspects of the relationship between acquired hearing loss and the impairment of intelligence. In general, the expected association was confirmed. CONCLUSIONS: By and large,we can expect acquired hearing loss to lead to an impairment of fluid intelligence. In the long-term, such a loss can also reduce the crystallized intelligence. Such decreases are disadvantageous in many areas of an information based society.

Adult↗
PubMed2002

Metabolism of metamizol in early stages of the incubated hen's egg.

In a previous paper we introduced a model for studying the metabolism of xenobiotics in the incubated hen's egg. This model is characterized by application of the xenobiotic into the yolk sac and identification of metabolites in the allantoic fluid (AF). Depending on the stage of development, the incubated hen's egg can be used both conservatively--in the sense of an animal experiment--and alternatively as a complementary method (appr. first half of incubation period). In the present investigation we used the sodium salt of [(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-lH-pyrazol-4-yl)-N-methylamino] methanesulfonic acid (1; metamizol, dipyrone) as model substance. Concentrations of 1 up to 32 mg/egg did not affect the viability of the incubated eggs. After inoculation of 1 (10 mg/egg) on the sixth day of incubation (DI) eight compounds were identified in the AF on DI 11 (TLC, GC, GC-MS, synthesis, MS, 13C NMR): 4-methylamino-(2), 4-amino-(3), 4-hydroxy-(4), 4-acetylamino-(5), 4-N-acetyl-N-methylamino-(6), 4-N-hydroxyacetyl-N-methylamino-(7), 4-N-hydroxyoxalyl-N-methylamino-(8) and 4-N-formyl-N-methylamino-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol- 3-one (-antipyrine; 9), respectively. Main metabolites are 2 and 5; 4 and 7 occur as sulfate or glucuronide conjugates. Compound 7 is also eliminated in it's free form. To our knowledge 7 has been detected as a new metabolite of 1 for the first time. The metabolic route of 7 was elucidated after application of 6. Compounds 8 and 9 are artefacts of 7. The data presented here demonstrate the usefulness of the developed model also in early stages of the incubated hen's egg. Consequently, the model is suitable as a complementary method for xenobiotic metabolism.

Allantoin↗
PubMed2001

Effects of miltefosine and other alkylphosphocholines on human intestinal parasite Entamoeba histolytica.

The protozoan parasite Entamoeba histolytica is the cause of amoebic dysentery and liver abscess. It is therefore responsible for significant morbidity and mortality in a number of countries. Infections with E. histolytica are treated with nitroimidazoles, primarily with metronidazole. At this time, there is a lack of useful alternative classes of substances for the treatment of invasive amoebiasis. Alkylphosphocholines (alkyl-PCs) such as hexadecyl-PC (miltefosine) were originally developed as antitumor agents, but recently they have been successfully used for the treatment of visceral leishmaniasis in humans. We examined hexadecyl-PC and several other alkyl-PCs with longer alkyl chains, with and without double bond(s), for their activity against two strains of E. histolytica. The compounds with the highest activity were oleyl-PC, octadecyl-PC, and nonadecenyl-PC, with 50% effective concentrations for 48 h of treatment between 15 and 21 microM for strain SFL-3 and between 73 and 98 microM for strain HM-1:IMSS. We also tested liposomal formulations of these alkyl-PCs and miltefosine. The alkyl-PC liposomes showed slightly lower activity, but are expected to be well tolerated. Liposomal formulations of oleyl-PC or closely related alkyl-PCs could be promising candidates for testing as broad-spectrum antiprotozoal and antitumor agents in humans.

Animals↗
PubMed2001

Structurally related immunological effects of triterpenoid saponins.

The influence of the triterpenoid saponins 1-10 has been investigated on murine spleenocytes in the lymphocyte transformation test and on murine macrophages in an phagocytosis assay. The lymphocyte transformation test and the phagocytosis assay showed that the tested compounds have no stimulating effect. However, a significant inhibition of lymphocyte proliferation by the triterpenoid saponins 2, 6 and 10 was demonstrated.

Animals↗
PubMed2000

Management of patients with community-acquired pneumonia in a primary care hospital: a critical evaluation.

The aim of the study was to evaluate routine management of patients with community-acquired pneumonia (CAP) with regard to severity patterns, diagnostic approaches and results, as well as initial empiric antimicrobial treatment and its impact on outcome. Two hundred and thirty-two consecutive patients with CAP admitted to a primary care hospital were studied prospectively. Patients were classified according to Fine's severity score. Severe pneumonia was defined as admission at the ICU. Diagnostic approaches and initial antimicrobial treatment were judged according to the guidelines of the European Respiratory Society (ERS). Fifty-five patients (24%) had mild, 156 (67%) moderate, and 21 (9%) severe CAP. At least one microbial examination was performed in 124 patients (54%). There was no association between microbial investigation and severity of CAP. Inadequate initial antimicrobial treatment was significantly more frequent in severe (18/21, 86%), than in mild (5/55, 9%) and moderate CAP (39/156, 25%, P < 0.0001). Conversely, antimicrobial overtreatment occurred significantly more often in mild (30/55, 55%) and moderate (77/156, 49%) than in severe CAP (0/21, 0%, P < 0.0001). Inadequate initial antimicrobial treatment was more frequent in non-responders [18/62 (29%) vs. 31/170, (18%), RR 1.6 95% CI 0.9-2.6, P = 0.07] and was associated with a longer duration of hospitalization (17 +/- 11 vs. 14 +/- 8 days, P = 0.03). Mortality was not affected by inadequate initial antimicrobial treatment [5/62 (8%) vs. 10/170 (6%), RR 1.4 95% CI 0.5-3.9, P=0.55]. Principal conceptual weaknesses which might be subject to intervention were (1) the hospitalization of patients with mild pneumonia at low risk of mortality; (2) the lack of association between microbial investigation and severity of CAP; (3) antimicrobial overtreatment of patients with non-severe CAP; and (4) inadequate antimicrobial treatment with increased number of primary treatment failures and duration of hospitalization.

Adult↗
PubMed1999

Triterpenoid saponins from Fagonia indica.

Two new triterpenoid saponins, 3-O-{[beta-D-glucopyranosyl-(1-->2)]-[alpha-L-arabinopyranosyl-(1- ->3)]- alpha-L-arabinopyranosyl}-ursolic acid-28-O-[beta-D-glucopyranosyl] ester (indicasaponin A), 3-O-{[beta-D-glucopyranosyl-(1-->2)]-[alpha-L-arabinopyranosyl-(1- ->3)]- alpha-L-arabinopyranosyl}-oleanolic acid-28-O-[beta-D-glucopyranosyl] ester (indicasaponin B) and two known triterpenoid saponins, 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]-ur solic acid-28-O-[beta-D-glucopyranosyl] ester, 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]-olean olic acid-28-O-[beta-D-glucopyranosyl] ester have been isolated from Fagonia indica. The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of 1H-1H COSY, NOESY, ROESY, TOCSY, HMQC and HMBC experiments.

Carbohydrate Conformation↗
PubMed1999

Comparative validation of prognostic rules for community-acquired pneumonia in an elderly population.

The aim of the study was to validate the prediction rule of M.J. Fine and coworkers for clinical outcome variables and three prognostic rules for the individual outcome of community-acquired pneumonia in an elderly population (rule 1: respiratory frequency > or =30 breaths x min(-1), diastolic blood pressure < or =60 mmHg, blood urea nitrogen >7 mM; rule 2: respiratory frequency > or =30 breaths x min(-1), diastolic blood pressure < or =60 mmHg, mental confusion; and rule 3: systolic blood pressure < or =80 mmHg, cardiac frequency > or =90 beats x min(-1), lactate dehydrogenase activity > or =260 IU x L(-1); death was predicted in the presence of at least two of three parameters). Overall 168 consecutive episodes of community-acquired pneumonia in patients aged > or =65 yrs and hospitalized in a primary care hospital were studied prospectively. Fine's rule was tested for its ability to predict length of hospital stay, requirement for intensive care unit (ICU) admission and death. For the three prognostic rules of individual outcome, performance regarding predicting death was determined. Mortality was 17/168 (10%). Fine's rule accurately predicted length of stay, the requirement for ICU admission and the risk of death from pneumonia as compared to the original derivation and validation cohorts. All three rules achieved moderate-to-high specificity (73%, 88% and 80%, respectively) and high negative predictive values (95%, 94% and 93%, respectively) but had a low sensitivity (65%, 47% and 47%, respectively). Rule 2 most closely reflected the risk of death from pneumonia when Fine's classification was used as reference. Fine's rule proved to give valid estimations regarding clinical outcome variables of community-acquired pneumonia in the elderly. The prognostic rules may be useful in determining individual patients at lower risk of death caused by pneumonia.

Aged↗
PubMed1998

Differential time course of angiotensin-induced AP-1 and Krox proteins in the rat lamina terminalis and hypothalamus.

We studied the time course of expression of the inducible transcription factors (ITF) c-Fos, FosB, c-Jun, JunB, JunD, Krox-20 and Krox-24, induced by a single intracerebroventricular injection of angiotensin II, in the subfornical organ (SFO), median preoptic nucleus (MnPO) paraventricular nucleus (PVN) and supraoptic nucleus (SON). c-Fos and Krox-24 were expressed rapidly in neurons of all four areas but completely disappeared after 4 h. FosB showed a delayed but persistent expression between 4 h and 24 h in the MnPO and PVN. c-Jun was induced in the MnPO, SFO and PVN after 1.5 h and in the SON after 4 h. JunB was selectively expressed in the MnPO and SFO and the level of JunD did not change. The expression of the pre-existing transcription factors SRF, CREB and ATF-2 which contribute to the transcriptional control of jun, fos and krox genes, was not affected by Ang II. Thus, we could show for the first time that an acute stimulation of AT receptors results in continual changes in ITF expression over 24 h.

Angiotensin II↗
PubMed1997

Triterpenoid saponins from the roots of Zygophyllum species.

Two new triterpenoid saponins, 3-O-[beta-D-2-O-sulphonylglucopyranosyl]-quinovic acid-28-O-[beta-D-glucopyranosyl] ester (zygophyloside G), 3-O-[alpha-L-arabinopyranosyl-(1-->2)-beta-D-quinovopyranosyl++ +]-quinovic acid-28-28-O-[beta-D-glucopyranosyl] ester (zygophyloside H), and seven known saponins have been isolated. The structures were established primarily on the basis of NMR spectroscopy. The assignment of all NMR signals was performed by means of 1H-1H COSY-45, NOESY, TOCSY, 13C APT, HMQC and HMBC experiments. The determination of the glycosylation sites was possible by the HMBC experiments.

Magnetic Resonance Spectroscopy↗