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Biomedical subjects

B Ahrens

Publications and source records attributed to B Ahrens.

At least 55 records · Page 3Linked to original sources
PubMed1995

Screening and identification of sumatriptan and its main metabolite by means of thin-layer chromatography, ultraviolet spectroscopy and gas chromatography/mass spectrometry.

Sumatriptan (CAS 103628-46-2, 3-[2-(dimethylamino)ethyl]-N-methyl-1H-indole-5-methanesulphonamide++ +), a substance for treatment of acute migraine attacks, and its main metabolite are investigated by thinlayer chromatography (TLC), ultraviolet spectroscopy, and gas chromatography/mass spectrometry (GC/MS). The resulting analytical data (correlated hRf-values, UV solvent spectra, remission spectra, GC retention indices, and electron impact (EI) mass spectra) including an extraction procedure and different derivatization methods are presented. Their applicability is described for urine analysis.

Biotransformation↗
PubMed1995

[Suicidal behavior of depressed patients at inpatient admission].

Early recognition of suicidal behavior is of extreme importance for avoidance of this cause of death. The risk of suicide attempts is particularly high in psychiatric illness, and among hospital in-patients especially in those with depression. Thus, the risk of suicide should be estimated in the first interview after admission to a psychiatric hospital. Our study analysed the routine documentation of such interviews on admission to the Psychiatrische Klinik der Freien Universität in Berlin: 41% of all depressive patients were suicidal. Suicidal and non-suicidal depressive patients could be differentiated by the following traits: suicidal patients were younger, had been younger at the initial onset of depressive illness, had made more suicide attempts in the past, and had a greater number of relatives who had committed suicide or made suicide attempts. They were more often single or divorced, and had fewer children of their own. Their psychopathology was characterized by a more strongly developed syndrome of depression, hostility and apathy. These findings point to a pattern of characteristics that are linked with suicidal behavior, which can be used to estimate the risk of suicide right at the beginning of a stay in hospital.

Adult↗
PubMed1994

Implications of the concepts "coping" and "quality of life" for criteria of course and outcome.

The Berlin Coping Study is a prospective longitudinal project with schizophrenic patients investigating the relationship between coping strategies and course and outcome. We find that some psychological issues relevant for both clinical practice and psychiatric research, and especially for pharmacological therapy, have been rather neglected up to now. The investigation of coping strategies leads to accentuating the patients' subjective individual views concerning their demands, goals, and coping activities in daily living and their schizophrenic illness. The concept of quality of life is increasingly receiving attention in various domains of professional care and it is very relevant to the issues discussed here. Consequences of this approach for therapy and research are outlined.

Adaptation, Psychological↗
PubMed1994

Reduced mortality, the ultimate indicator of treatment efficacy. Review and perspectives.

Since psychiatric patients are at risk for increased mortality, one of the strongest indicators of treatment efficacy is a normalized mortality. The question arises as to whether it is possible to change the mortality by different treatment strategies. Surprisingly, intervention studies using death or survival as an endpoint are relatively rare in psychiatry, although in other medical disciplines this approach is very common. A review of the few existing investigations of the influence of somatic therapy on mortality--these mainly relate to affective disorders--suggests that in principle adequate somatic treatment can reduce the high mortality risk in these disorders. A reduced mortality can be observed, particularly during long-term lithium treatment. The question to what extent a somatic therapy can protect psychiatric patients against premature death cannot be answered in a one-dimensional way. There are various factors that can strengthen or weaken the possible benefits of drug therapy. Such influencing factors are the patient, the physician, and the treatment setting. Mortality studies are important to identify the individual factors that influence treatment efficacy. With reference to the role of the moderating variables, the aims of future research in the area of treatment efficacy in psychiatry will be addressed.

Humans↗
PubMed1994

Mortality during initial and during later lithium treatment. A collaborative study by the International Group for the Study of Lithium-treated Patients.

We have previously shown that the mortality of patients with recurrent affective disorders in long-term lithium treatment is not higher than that of the general population. In the present study on 471 patients from Denmark and Germany, we examined mortality during the initial year of lithium treatment and during later lithium treatment. During initial lithium treatment, the total mortality was twice as high as in the general population (difference not significant) and the mortality due to suicide 16 times higher. During later lithium treatment, the mortality rates did not differ from those in the general population. Our results indicate that patients with frequent, often severe recurrences, those chosen for prophylactic lithium treatment, are at risk of high mortality, which then diminishes as the prophylactic action of the treatment takes effect.

Adult↗
PubMed1994

Screening, identification and determination of the two new hypnotics zolpidem and zopiclone.

This article reports basic analytical data for screening and detection of the hypnotics zolpidem (CAS 82626-48-0) and zopiclone (CAS 43200-80-2) by using corrected hR-values, GC (gas chromatography) retention indices, UV solvent spectra and remission spectra. Beside this a HPTLC (high-performance thin-layer chromatography)-procedure for quantification is described.

Azabicyclo Compounds↗
PubMed1994

Modified screening procedure with fluorescence detection for flunitrazepam and its metabolites via acridine derivatives.

A modified thin-layer chromatographic method with fluorescence detection is described for the screening of flunitrazepam and its major metabolites in urine. The method is based on the hydrolysis and subsequent formation of acridine derivatives by cyclization in dimethyl-formamide. This reliable screening procedure, which has proven its usefulness in many laboratories, provides valid results in the absence of diclofenac, carbamazepine, and tricyclic antidepressants. On the other hand these latter substances are frequently detectable in urine samples taken from addicts especially during therapy. So it was necessary to modify the procedure.

Acridines↗
PubMed1993

Length of lithium treatment needed to eliminate the high mortality of affective disorders.

Recent studies have indicated that long-term lithium treatment reduces the expected suicidal activity and overall mortality of patients with affective disorders. Based on the data from the lithium clinics in Berlin and Hamilton (n = 512), a minimum length of two years of continued lithium treatment is needed to reduce the high mortality resulting from affective disorders.

Confidence Intervals↗
PubMed1992

The effect of long-term lithium treatment on the mortality of patients with manic-depressive and schizoaffective illness.

Clinical research centers in Aarhus, Berlin, Hamilton and Vienna collected mortality data for 827 manic-depressive and schizoaffective patients given lithium treatment for more than 6 months. The average duration of the treatment was 81 months and the total time on lithium 5600 patient-years. For each patient, the mortality risk was calculated by entering the appropriate national life tables for the general population. The number of observed deaths was 44; the number of expected deaths was 49.7. The standardized mortality ratio, 0.89, did not differ significantly from 1.0. The mortality of manic-depressive patients is 2-3 times that of the general population. Our data show that the mortality of manic-depressive and schizoaffective patients given long-term lithium treatment does not differ significantly from that of the general population.

Adult↗
PubMedDate not supplied

Trace contamination of over-the-counter androstenedione and positive urine test results for a nandrolone metabolite.

CONTEXT: Several anabolic steroids are sold over-the-counter (OTC) in the United States, and their production is not regulated by the US Food and Drug Administration. Reports have suggested that use of these supplements can cause positive urine test results for metabolites of the prohibited steroid nandrolone. OBJECTIVES: To assess the content and purity of OTC androstenedione and to determine if androstenedione and 19-norandrostenedione administration causes positive urine test results for 19-norandrosterone, a nandrolone metabolite. DESIGN: Randomized controlled trial of androstenedione, open-label trial of 19-norandrostenedione, and mass spectrometry of androstenedione preparations, conducted between October 1998 and April 2000. SETTING: Outpatient facility of a university hospital. PARTICIPANTS: A total of 41 healthy men aged 20 to 44 years. INTERVENTION: Participants were randomly assigned to receive oral androstenedione, 100 mg/d (n = 13) or 300 mg/d (n = 11) for 7 days, or no androstenedione (n = 13); in addition, 4 patients received 10 microg of 19-norandrostenedione. MAIN OUTCOME MEASURES: Content of OTC androstenedione preparations; level of 19-norandrosterone in urine samples, determined by mass spectrometry, compared among the 3 randomized groups at day 1 and day 7, and among the participants who received 19-norandrostenedione from October 1998 to April 2000. RESULTS: All urine samples from participants treated with androstenedione contained 19-norandrosterone, while no samples from the no-androstenedione group did. Urinary concentrations were averaged for day 1 vs day 7 measurements; mean (SD) 19-norandrosterone concentrations in the 100-mg/d and 300-mg/d groups were 3.8 (2.5) ng/mL and 10.2 (6.9) ng/mL, respectively (P =. 006). The 19-norandrosterone content exceeded the cutoff for reporting positive cases (>2.0 ng/mL) in 20 of 24. The androstenedione preparation used was pure at a sensitivity of 0.1%, but at 0.001% 19-norandrostenedione was found. For the 4 participants to whom 10 microg of 19-norandrostenedione was administered, 19-norandrosterone was found in all urine samples. Of 7 brands of androstenedione analyzed at the 1% level, 1 contained no androstenedione, 1 contained 10 mg of testosterone, and 4 more contained 90% or less of the amount stated on the label. CONCLUSION: Our study suggests that trace contamination of androstenedione with 19-norandrostenedione is sufficient to cause urine test results positive for 19-norandrosterone, the standard marker for nandrolone use. Oral steroid doses as small as 10 microg are absorbed and excreted in urine. Some brands of androstenedione are grossly mislabeled. Careful analysis of androstenedione preparations is recommended in all studies of its biological effects. JAMA. 2000;284:2618-2621.

Adult↗
PubMedDate not supplied

Suicidal behavior--symptom or disorder?

This article examines the diagnostic status of suicidal ideation with and without additional signs of defined or subthreshold mental disorders. Data from the World Health Organization (WHO) study on Psychological Problems in General Health Care (PPGHC) show that 8.8% of all general practice patients report that they recently had a wish to be dead. Among patients with acute depressive episodes, the rate is 34.5%, as compared with 1.3% in persons without any sign of mental disorder. Rates of suicidal ideation in persons with subthreshold disorders (10.4%) are similar to the rate in persons with other, nondepressed forms of mental disorders (12.9%). Still, 30.1% of all persons with suicidal ideation do not have a defined mental disorder, and 21.5% do not even have subthreshold disorders. But in these persons also, suicidal ideation is associated with an increased rate of depressive complaints. Suicidal ideation therefore, in any case, can be seen as an indicator of mental problems. But it seems impossible to lower the thresholds of defined mental disorders so that all forms of suicidal ideation will be covered. Instead, suicidal thoughts must be regarded as a symptom with the status of a disorder itself which should be handled as a comorbid condition if other mental disorders co-occur.

Comorbidity↗
PubMedDate not supplied

Heat shock protein 70: role in antigen presentation and immune stimulation.

Heat shock proteins (HSP) when released into the extracellular milieu can act simultaneously as a source of antigen due to their ability to chaperone peptides and as a maturation signal for dendritic cells, thereby inducing DCs to cross-present antigens to CD8+ T-cells. HSP can also act independently from associated peptides, stimulating the innate immune system. Previous results regarding the activation of NK cells by HSP70 cell surface expression on tumour cells and soluble HSP70 will be further covered elsewhere within this issue. For cross-presentation, HSP70-peptide complexes (HSP70-PC) were used from two human melanoma cell lines that differ in the expression of the tumour-associated antigen tyrosinase. Purified HSP70-PC consists of both the constitutively expressed HSC70 and the inducible HSP70. HSP70-peptide complexes purified from tyrosinase positive (HSP70-PC/tyr+) human melanoma cells, incubated with immature DCs, results in the activation of HLA-*A0201-restricted tyrosinase peptide-specific T-cells. Receptor-mediated uptake of HSP70-PC by DCs and intracellular transport are required for efficient MHC class I restricted cross-presentation of chaperoned peptides. Demonstration of HSP70-PC mediated cross-presentation of such non-mutated naturally expressed tumour antigens is of special clinical interest with regard to hyperthermia. Tumour regression and improved local control have been shown within clinical phase II/III trials integrating regional hyperthermia combined with radiation and/or chemotherapy in multimodal treatment strategies. According to the proposed concept, local necrosis induced by hyperthermic treatment induces the release of HSPs, followed by uptake, processing and presentation of associated peptides by DCs. By acting as chaperone and a signal for DC maturation, HSP70-PC might efficiently prime circulating T-cells. Therefore, upregulating HSP70 and causing local necrosis in tumour tissue by hyperthermia offers great potential as a new approach to directly activate the immune system.

Animals↗
PubMedDate not supplied

Classic conditioning and dysfunctional cognitions in patients with panic disorder and agoraphobia treated with an implantable cardioverter/defibrillator.

OBJECTIVE: A model for the development of anxiety disorders (panic disorder with or without agoraphobia) is needed. Patients with an implantable cardioverter/defibrillator (ICD) are exposed to repeated electric shocks. If the theory of anxiety development by aversive classic conditioning processes is valid, these repeated shocks should lead to an increased risk of anxiety disorders. To study this hypothesis, we retrospectively studied 72 patients after implantation of an automatic ICD. METHODS: Patients were assessed with the semistructured Diagnostic Interview of Psychiatric Disease 1 to 6 years after implantation of an automatic ICD. Panic disorder and/or agoraphobia was diagnosed in patients who fulfilled all DSM-III-R criteria for those conditions. RESULTS: Anxiety disorder developed in 15.9% of patients after ICD implantation. This was significantly related to the frequency of repeated defibrillation (shocks) to stop malignant ventricular arrhythmias. Dysfunctional cognitions are an additional vulnerability factor. CONCLUSIONS: The data support both the conditioning hypothesis and the cognitive model of anxiety development. These findings suggest that ICD patients are an appropriate risk population for a prospective study of the development of anxiety disorders.

Aged↗
PubMedDate not supplied

Allergic sensitization and allergen exposure during pregnancy favor the development of atopy in the neonate.

BACKGROUND: Several studies have considered that the in utero environment plays an important role in the onset of the allergic phenotype. We assessed whether allergic sensitization and allergen exposure during pregnancy favor the postnatal onset of allergy in the neonate. METHODS: BALB/c mice were sensitized to ovalbumin (OVA) before mating followed by allergen aerosol exposure during pregnancy. T and B cell responses in offspring were followed up until day 60 postpartum. At the age of 4 weeks offspring were exposed to a heterologous antigen, beta-lactoglobulin (BLG). RESULTS: Pregnant mice developed immediate hypersensitivity responses and Th-2/ Th-0 immunity following allergen aerosol exposure. At birth, T cells from offspring of nonsensitized BALB/c mice were characterized by an impaired IFN-gamma production, which was lowered even further in offspring of OVA-sensitized BALB/c mice. Offspring of OVA-sensitized BALB/c mice responded with immediate-type cutaneous hypersensitivity reactions to OVA which could be related to the pre- and postnatal transfer of maternal OVA-specific IgG1 antibodies. After exposure to BLG, offspring of OVA-sensitized BALB/c mice developed an accelerated Th-2-driven immune response compared to offspring from nonsensitized BALB/c mice as indicated by enhanced anti-BLG IgG1 antibody production and increased numbers of positive immediate-type cutaneous hypersensitivity reactions to BLG. CONCLUSION: Our data suggest that Th-2/Th-0 immunity present during pregnancy has a decisive impact on shaping the Th-1/Th-2 T cell profile in response to postnatal allergen exposure.

Allergens↗
PubMedDate not supplied

[Detection of the cholinesterase inhibitor tacrine and its main metabolites].

Tacrine, a cholinesterase inhibitor for symptomatic treatment of minor to moderate dementia, and its primary metabolites 1-hydroxy-tacrine and 4-hydroxy-tacrine were studied by means of thin-layer chromatography, UV spectroscopy and gas-chromatography/mass spectroscopy. The analytical data (corrected hRf values, UV spectra in solution as well as reflectance spectra, high-pressure liquid chromatography data, GC retention indices and EI mass spectra) including various derivatization methods are described.

Biotransformation↗