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Biomedical subjects

B Richter

Publications and source records attributed to B Richter.

At least 91 records · Page 5Linked to original sources
PubMed1995

Structure-activity relationships in allergic contact dermatitis (I). Studies on the influence of side-chain length with derivatives of primin.

Primin (2-methoxy-6-pentyl-1,4-benzoquinone) is a naturally-occurring strong sensitizer from Primula obconica (Primulacease). To determine the effect of side-chain length on sensitizing potency, 15 analogues with linear side chains from C1 to C15 and 4 C6-analogues with branched side chains were prepared synthetically and devoted to experimental sensitization in guinea pigs. The results showed an increase of the sensitizing capacity with increasing length of the alkyl side chain from C1 to C10, reaching a maximum at C11 and C12. On further elongation, the sensitizing potency decreased beyond C13, reaching values which finally were as low as those of the C1 and C3 derivatives. The results mirror findings which formerly have been obtained with other non-quinonoid compounds like catechols, phenols, hydroquinones and gallates. In the plant kingdom, compounds approximating an "ideal allergen" consisting of a quinonoid ring with a 10 or 11 carbon-membered side chain have been identified only once: 2,3-dimethoxy-geranyl-1,4-benzoquinone, a remarkably strong sensitizer found in Wigandia caracasana (Hydrophyllaceae).

Animals↗
PubMed1995

Some Remarks on the Classification of Subjective Idiopathic Tinnitus (SIT) - An Essay toward Establishing a Cross-matched Grading System.

To better quantify levels of individual impairment caused by SIT, two different sets of classification were cross matched. This combination factored in the inaccuracy caused by terminologic inexactitude. Although the system which developed historically had a subjective bias, the newer tests created to analyze tinnitus specifically were far more objective. By combining the findings of both tests using a numeric score, rating tinnitus should become more exact. Classification of tinnitus began long ago in ancient Babylon. In the library of the court of King Assurbanipal (668 to 626 B.C.), clay slates were found which gave the first written classification of tinnitus. Later Pliny, Paracelsus, Itard, and Politzer developed separate systems of tinnitus classification.(2) All these systems can be broken down into the branches of epidemiology, etiology, and legal requirements. Epidemiology gives information on tinnitus in "terms of time, place, and persons." Etiology provides a means to summarize the relationships between the subjective findings of tinnitus and relationships in terms of pathoetiology. It is the large numbers of single complaints about tinnitus and possible associated relationships of pathologic relationships that cause the different clinical classification of tinnitus. In terms of legal disability, a more accurate classification will permit graduated comprehensions of the irritation experienced by the patient and related personal, social and occupational interferences. Measuring these grades of impairment will allow comparison of different types of tinnitus. Unlike other audiologic failures such as generalized hearing loss and disturbances of equilibrium resulting from vestibular affections, assessment of the intensity of tinnitus and its involvement in personal life is restricted by limitations, because each classification system contains inaccuracies per se.

Journal Article↗
PubMed1995

Pseudo-pseudohypertriglyceridemia: a case of increased free glycerol without evidence for glycerol kinase deficiency.

High concentrations of glycerol in plasma may result in overestimation of triglycerides in chemical and enzymatic assays. Known causes of increased glycerol concentrations in blood include glycerol-contaminated blood-collector tubes and pseudohypertriglyceridemia, a condition caused by genetic defects in the gene for glycerol kinase. We report a patient with sudden hearing loss who presented with an increased blood glycerol concentration after undergoing an oral glycerol test.

Adult↗
PubMed1995

[Relapse in alcoholism during inpatient therapy. Empirical facts and practical recommendations for relapse management].

The contribution resumes the most important empirical results on the phenomenon of alcoholic relapse during inpatient-treatment. Results and clinical considerations lead to the opinion to abandon the classic position of disciplinary discharge after inpatient relapse without deviating from the ideal target of abstinence. Proposals are made for the practical management of relapses during inpatient-treatment. Finally, it is demanded for empirical studies on this taboo field of addiction treatment for deciding the questions of continued treatment or discharge after inpatient alcoholic relapse.

Alcoholism↗
PubMed1995

[3 different malignancies of the aerodigestive tract after chronic abuse of cannabis products].

The occurrence of multilocular malignant tumors in the upper aerodigestive tract in young patients with known marijuana abuse has been described by other authors. A case of a 28-year-old man who was known to abuse alcohol, nicotine and cannabis for some years is presented. He suffered simultaneously from a squamous cell carcinoma of the hypopharynx with bilateral cervical metastases, an adenocarcinoma of the transverse colon and a primary hepatocellular carcinoma. This case is the first reported that shows the occurrence of three separate malignant tumors with different histologies in the aerodigestive tract which could be related to a chronic abuse of cannabis.

Adenocarcinoma↗
PubMed1994

[Effects of therapy of laryngeal and hypopharyngeal cancers on eustachian tube function].

In a prospective investigation Eustachian tube function was tested before and after surgery and irradiation of patients suffering from carcinoma of the larynx or hypopharynx. Passive and active tubal parameters were determined using the dual-impedance method in a pressure chamber. In this test, passive tubal function is described by the spontaneous opening and closing characteristics of the tube by an overpressure in the middle ear. Active tubal parameters are determined by the facility of the tube to equalize an over- and underpressure in the middle ear by swallowing. Statistic evaluation was performed with Student's t-test. There were no significant alterations of passive or active tubal function after neck dissection with or without surgery of the primary tumour. On the other hand we observed significant deterioration of all tubal parameters immediately after a series of fractionated percutaneous telecobalt therapy (60 Gy). 2 out of 18 patients developed unilateral middle ear effusion during irradiation which was reversible within 6 months. In most patients we observed a total or at least partial restitution of passive tubal parameters during this time, which was statistically significant. The active tubal function was of minor reversibility. Whereas the facility to equalize a positive pressure in the middle ear was quite good after 6 months, only few patients were able to equalize a negative pressure. The temporary deterioration of passive tubal function may be caused by a marginal implication of the tube at the edge of the irradiation field and by increased lymphatic pressure in tubal tissue following a radiogenic swelling of the lymphatic vessels of the neck.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1994

[Predicting load bearing of the hip joint. Computerized analysis with a 3-D multibody model of the human].

Multibody analysis was applied to construct an advanced model of the human body, where the large joints and complete mass and inertial properties were implemented. The model represents the 50th-percentile rank of a male adult. The hip joint is controlled by three muscle forces. The muscle coordinates were taken from a data source, previously collected by our group. The model enables one to analyze 3D hip joint forces with respect to various joint angles and represents conceptually an improvement of the classical method of graphical statics, which was established by Pauwels [15]. A hip joint load of three times body weight was found in the single leg stance. A load of 3.7 times body weight was calculated when simulating a knee flexion angle of 90 degrees, and a ventral inclination of the resultant hip joint force was seen. A constant amount of gluteus medius muscle force was observed during flexion. An increasing flecting moment at the hip joint, however, had to be balanced by a significantly increased gluteus maximus muscle force. As a consequence, torsional forces can be studied by the system presented here and should also be considered when testing stems of hip prostheses. External muscle and joint forces are provided and can be used as input data for stress analyses.

Adult↗
PubMed1994

Dependence of distortion product emission amplitude on primary-tone stimulus levels during middle-ear pressure changes.

The measurement of distortion product otoacoustic emissions (DPOAEs) is dependent upon their transmission through the middle ear. The purpose of this study was to measure the combined effects of primary-tone level variation and of middle-ear pressure alterations on DPOAE amplitudes. Twenty ears of normally hearing adults were examined. Four DPOAEs were measured at the frequency 2f1-f2 (614 Hz, 1342 Hz, 2921 Hz, 6341 Hz), with the associated geometric mean (GM) of the primary tones at 1, 2, 4, and 8 kHz. Ambient air pressure was varied in a pressure chamber between 0 kPa and 6 kPa in 2-kPa steps. At each pressure level, L1 or L2 was varied in 5-dB steps between 40 and 60 dB HL with a corresponding fixed level of either L1 or L2 of 40 dB HL. The DPOAE amplitudes showed frequency-dependent changes. The largest mean amplitude reduction with pressure variations could be observed for the DPOAE at 614 Hz, whereas the DPOAEs at 6341 Hz remained practically unaffected. During variation of primary-tone levels, the maximum DPOAE amplitude generally occurred, independent of middle-ear pressure, when L1 was 5 to 15 dB greater L2. The results have implications for clinical measurements in that DPOAEs may be detected in the high-frequency range even under pathologically altered middle-ear pressure, and the optimum difference L1-L2 that produces maximum DPOAE amplitude is relatively unaffected by middle-ear pressure.

Acoustic Stimulation↗
PubMed1994

Thyroid surgery in untreated severe hyperthyroidism: perioperative kinetics of free thyroid hormones in the glandular venous effluent and peripheral blood.

BACKGROUND AND METHODS: It is generally believed that thyroid surgery in Graves' disease requires a euthyroid state to avoid thyrotoxic reactions. We carried out a prospective study on 23 patients who had severe hyperthyroidism with free thyroid hormone concentrations (fT3 or fT4) exceeding the upper normal boundary by 300% or more and who were not pretreated with thyrostatic agents. We determined hormone levels during operation in the thyroid venous effluent before and after surgical trauma and monitored their postoperative elimination kinetics. RESULTS: The concentration of fT3 and fT4 in the venous effluent of the hyperactive gland did not exceed the peripheral levels. Surgery did not induce any intraoperative or postoperative increase in fT4 or fT3, whereas thyroglobulin concentrations rose sharply. Both fT4 and fT3 followed biphasic elimination kinetics, and a significant decline of circulating free hormone concentrations was measurable within the first postoperative hour. CONCLUSIONS: Contrary to widely held assumptions, the surgical trauma does not stimulate the release of thyroid hormones. Hence this mechanism cannot account for the postoperative development of thyroid storm. Our observations imply that immediate operation should generally be considered for the emergency treatment of an imminent thyroid storm.

Adult↗
PubMed1993

Clinical pharmacology of human insulin.

Nowadays, human insulin is used daily by millions of diabetic patients. The biological effect of human insulin is comparable to that of porcine insulin. However, after subcutaneous injection, pharmacological and clinical studies showed pharmacokinetic and pharmacodynamic differences between human and animal insulins. Human insulin tends to have faster absorption and shorter duration of action compared with animal insulin. These differences are more pronounced and can be of clinical relevance with intermediate- and long-acting insulin preparations. Optimal metabolic control can be achieved with either human or highly purified animal insulin preparations, provided appropriate insulin replacement strategies are used.

Animals↗
PubMed1993

Cost-effectiveness of a structured treatment and teaching programme on asthma.

The purpose of this study was to perform a cost-effectiveness analysis of the structured treatment and teaching programme for patients with asthma (ATTP) at Düsseldorf University. We investigated whether the monetary benefits outweighed the costs of the intervention. Adult patients with moderate to severe asthma participated in a 5 day in-patient programme. Follow-up was 3 yrs. The incremental costs and benefits of the intervention, compared with standard treatment, were calculated. Costs were incurred by the hospitalization and by lost productivity. Compared to the year before the programme, (average reduction) days spent in hospital (5.2 days per patient per year), days of absence from work (18.4 days per patient per year), acute severe asthma attacks (3.8 attacks per patient per year), and physician consultations (2.3 visits per patient per month), decreased in the 3 yrs after the intervention. The programme produced net benefits of DM 12,850 (in 1991 German marks) per patient within 3 yrs. Within the health care sector, the net benefits were DM 5,900. Within 3 yrs, the paying bodies saved DM 2.70, and society as a whole saved DM 5 on each DM spent for the programme. We conclude that the intervention produced net monetary benefits. This result was stable over a wide range of variation of the outcome measures. Therefore, programme deserves implementation, not only for its demonstrated medical benefits but also for its economic savings.

Absenteeism↗
PubMed1993

[Cortisone level and emotional support by key figures in patients with bronchial asthma].

In a subgroup of patients with bronchial asthma, irrational fears of cortisone medication can be observed beyond justified worries about side-effects. A cortisone image which involves overemphasizing the threatening aspects of cortisone, often underlies noncompliant illness behaviour. In the present study, cortisone image and subjectively experienced emotional support by a key figure was investigated in 62 patients, all of whom had participated in the Düsseldorf Asthma treatment and teaching programme (ATTP). The data show that patients having a supportive relationship with their key figures are less likely to experience threatening aspects of cortisone. The findings are discussed in light of psychoanalytic object relations theory.

Adaptation, Psychological↗
PubMed1992

[Plasma- and tissue concentrations following intramuscular administration of etofenamat. Pharmacokinetics of etofenamat and flufenamic acid in plasma, synovium, and tissues of patients with chronic polyarthritis after administration of an oily solution of etofenamat].

Studies on Plasma and Tissue Concentrations of Etofenamate following Intramuscular Application/Pharmacokinetics of etofenamate and flutenamic acid in plasma, synovia and tissues of patients with chronic polyarthritis after application of oily etofenamat solution Pharmacokinetics of etofenamate (ETO, CAS 30544-47-9; Rheumon i.m.) and flufenamic acid (FLU, CAS 530-78-9) were investigated in plasma, synovial fluid, and tissues after single intramuscular application of etofenamate to patients with rheumatoid arthritis. 62 patients with indicated operative procedure in the knee-joint received a single dose of etofenamate dissolved in oil before operation. At definite times between 1.5 and 48 h post injectionem samples from 6 patients of each time group were collected. Samples of plasma, synovial fluid, synovial membrane, muscle, bone, hyaline cartilage, and fat tissue and in some cases meniscus cartilage were taken. Concentrations of ETO and its active metabolite, FLU, were determined by HPTLC. In all tissues investigated, concentration/time courses of ETO and FLU were observed. ETO and FLU were measured first in all matrices 1.5 h at the latest 3 h post injectionem. Pharmacokinetics in tissues follows that in plasma. Rate-limiting step is the liberation of drug from the oil depot. For a long period pharmacokinetics of ETO and FLU is mainly determined by the constant liberation from the oil depot (zero order kinetics of liberation). Zero order kinetics is deduced from the linear ascent of the cumulated AUC (in percent) vs. time plot. It is directly related to the liberation of drug from the galenical formulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Negative cortisone attitude in patients with bronchial asthma].

Patients with bronchial asthma often exhibit irrational fears of cortisone medication beyond justified worries about side-effects. A negative cortisone image, which means overemphasizing the damaging and threatening aspects of cortisone, often underlies non-compliant illness behaviour. In the present study, cortisone image was investigated in 54 patients with bronchial asthma before and after participation in the Düsseldorf Asthma treatment and teaching programme (ATTP) and one year later. By participating in ATTP, a significant reduction of the negative cortisone image and thus a more realistic view of cortisone could be achieved in most patients. This effect was also evident at the follow-up examination one year later. On the other hand, persistence of a negative cortisone image in a subgroup of patients turned out to be a potent predictor of later non-compliant illness behaviour. Psychological implications of a persistent negative cortisone image are discussed.

Adult↗
PubMed1992

[Affective-cognitive coping with attacks and illness behavior in patients with bronchial asthma].

The purpose of this study was to investigate attack-related cognitive coping styles in 80 patients with bronchial asthma and to relate them to outcome parameters of illness behaviour. All patients had participated in a 5-day-lasting asthma treatment and teaching programme (ATTP). Outcome variables to be predicted were: The number of days in hospital due to asthma during the year following the training programme and the patients' adherence to the recommendations of the programme one year later. Independent predictor variables were: pre-training attack frequency, hospitalization due to asthma, medication intensity, pulmonary function, asthma symptom anxiety, trait anxiety and attack-related cognitive coping styles. Multiple regression analyses show the importance of a "minimizing/self-confident" coping style in predicting days in hospital, while a "diverting" style predicts best a poor management of attacks in patients on oral steroids.

Adaptation, Psychological↗