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Biomedical subjects

J Richter

Publications and source records attributed to J Richter.

At least 19 recordsLinked to original sources

Fatty acids and sleep in depressed inpatients.

Sleep disturbances belong to the most frequent symptoms of depression. Low concentrations of n-3-fatty acids might represent one determinant within that process. Therefore, the aim of the study was to examine the relationships between serum fatty acid concentrations and severity of sleep disturbances in depressives. Serum fatty acids were measured gaschromatographically in 118 depressive inpatients (51 males; 67 females; age 45.4+/-12.0 years), divided into subgroups according to three degrees of sleep disturbances (BDI-item). At admission and discharge, we found significant negative correlations between the degree of sleep disturbances and fatty acid concentrations (myristic, palmitic, palmitoleic, oleic, linoleic, eicosadienoic and docosahexaenoic acid). At both assessments palmitoleic and eicosadienoic acids had the strongest connections with sleep performance. Palmitoleic and oleic acid seem to be especially important for sleep disorders, may be due to their function as precursors of the sleep inducing oleamide. Linoleic and eicosadienoic acid could be helpful for maintaining sleep because they are precursors of the sleep mediator PGD2. In contrast to our hypothesis, there is not only a significant lack of n-3 fatty acids but also of special monoenoic and n-6 fatty acids in sleep-disturbed depressives.

Adult↗

Quantum J1-J2 antiferromagnet on a stacked square lattice: influence of the interlayer coupling on the ground-state magnetic ordering.

Using the coupled-cluster method and the rotation-invariant Green's function method, we study the influence of the interlayer coupling Jperpendicular on the magnetic ordering in the ground state of the spin-1/2 J1-J2 frustrated Heisenberg antiferromagnet (J1-J2 model) on the stacked square lattice. In agreement with known results for the J1-J2 model on the strictly two-dimensional square lattice (Jperpendicular=0), we find that the phases with magnetic long-range order at small J2 Jc2 are separated by a magnetically disordered (quantum paramagnetic) ground-state phase. Increasing the interlayer coupling Jperpendicular >0, the parameter region of this phase decreases, and, finally, the quantum paramagnetic phase disappears for quite small Jperpendicular approximately (0.2-0.3)J1.

Journal Article↗

[Disability in lupus erythematosus].

Morbidity and co-morbidities in patients with lupus erythematosus (LE) result in an impairment, limiting activities of daily living. We compared the handicap, appraised by the German welfare system in patients with LE and their diagnosis, morbidities and co-morbidities, therapy, functional capacity, psychological status and general health. The data were obtained in an anonymous self-administered questionnaire conducted by the lupus patient association. 892 data sets were available for the trial. The mean age was 46.9y, disease duration was 10.3y. The patients had 3.8 concomitant diseases on average. 39.7% were still working and 35.4% drew a pension. 59.2% made an application for disability, which wasn't assigned in only 2.5% of cases. 82.6% had an average grade of disability of more than 50%. It demonstrated a good correlation to age, disease duration, type of LE and therapy. Predictors for a worse assessment were disease duration, osteoarthritis, cerebral insults and functional capacity. In conclusion the data demonstrate a fair appraisal of disability by the German welfare system in patients with LE. Self-administered questionaires can yield credible results.

Disability Evaluation↗

Changes in expression and distribution of claudin 2, 5 and 8 lead to discontinuous tight junctions and barrier dysfunction in active Crohn's disease.

BACKGROUND: Epithelial barrier function is impaired in Crohn's disease. AIM: To define the underlying cellular mechanisms with special attention to tight junctions. METHODS: Biopsy specimens from the sigmoid colon of patients with mild to moderately active or inactive Crohn's disease were studied in Ussing chambers, and barrier function was determined by impedance analysis and conductance scanning. Tight junction structure was analysed by freeze fracture electron microscopy, and tight junction proteins were investigated immunohistochemically by confocal laser scanning microscopy and quantified in immunoblots. Epithelial apoptosis was analysed in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling and 4',6-diamidino-2-phenylindole staining. RESULTS: Patients with active Crohn's disease showed an impaired intestinal barrier function as indicated by a distinct reduction in epithelial resistance. As distribution of conductivity was even, focal epithelial lesions (eg, microerosions) did not contribute to barrier dysfunction. Instead, freeze fracture electron microscopy analysis showed reduced and discontinuous tight junction strands. Occludin and the sealing tight junction proteins claudin 5 and claudin 8 were downregulated and redistributed off the tight junction, whereas the pore-forming tight junctions protein claudin 2 was strongly upregulated, which constitute the molecular basis of tight junction changes. Other claudins were unchanged (claudins 1, 4 and 7) or not detectable in sigmoid colon (claudins 11, 12, 14, 15 and 16). Claudin 2 upregulation was less pronounced in active Crohn's disease compared with active ulcerative colitis and was inducible by tumour necrosis factor alpha. As a second source of impaired barrier function, epithelial apoptosis was distinctly increased in active Crohn's disease (mean (SD) 5.2 (0.5)% v 1.9 (0.2)% in control). By contrast, barrier function, tight junction proteins and apoptosis were unaffected in Crohn's disease in remission. CONCLUSION: Upregulation of pore-forming claudin 2 and downregulation and redistribution of sealing claudins 5 and 8 lead to altered tight junction structure and pronounced barrier dysfunction already in mild to moderately active Crohn's disease.

Adult↗

The antioxidative power AP--A new quantitative time dependent (2D) parameter for the determination of the antioxidant capacity and reactivity of different plants.

In the last decade, naturally occurring antioxidants continue to play an important role in the food-supplement industry. The content of antioxidants in a plant depends on the species, temperature, humidity, period of growth, harvest month, part of the plant used and many other variables. Herein, we present a new method able to determine the all over antioxidative power (AP) of plant extracts or lyophilised plant parts based on the reducing activity against a stable test radical. The method is performed by ESR spectroscopy and is based on the well-known 1,1-diphenyl-2-picryl-hydrazil (DPPH) method with the major difference that both the antioxidative capacity and the antioxidative activity are used to characterise an antioxidant. The resulting antioxidative power is expressed in antioxidative units (AU), where 1AU corresponds to the activity of a 1 ppm solution of Vitamin C as a benchmark. This method allows a rapid, unexpensive and general applicable technique for the measurement of the antioxidative power of very different kinds of substances. The inclusion of the kinetic behaviour of the reducing process of the antioxidant for the determination of the AP allows the identification of the main antioxidant present in a sample. Herein, we present the application example of seeds, sprouts and adult parts of dandelion, amaranth, quinoa, fenugreek, broccoli, red clover and mugwort, where the AP method permits to characterise the plants with the highest antioxidant capacity and reaction velocity. The method permits to select active plant extracts for the food and nutrition industry.

Antioxidants↗

Induction of immunity and inflammation by interleukin-12 family members.

The interleukin (IL)-12 family is composed of three heterodimeric cytokines, IL-12 (p40p35), IL-23 (p40p19), and IL-27 (EBI3p28), and of monomeric and homodimeric p40. This review focuses on the three heterodimeric members of the IL-12 family. The p40 and p40-like (EBI3) subunits have homology to the IL-6R, the other subunits (p35, p19, and p28) are homologous to each other and to members of the IL-6 superfamily. On the basis of their structural similarity, it was expected that the members of the IL-12 family have overlapping pro-inflammatory and immunoregulatory functions. However, it was surprising that they also show very distinct activities. IL- 12 has a central role as a Th1-inducing and -maintaining cytokine, which is essential in cell-mediated immunity in nonviral infections and in tumor control. IL-23 recently emerged as an end-stage effector cytokine responsible for autoimmune chronic inflammation through induction of IL-17 and direct activation of macrophages. Very recently, IL-27 was found to exert not only a pro-inflammatory Thl-enhancing but also a significant anti-inflammatory function.

Animals↗

Evaluation for the fully automatic inlay reconstruction by means of the biogeneric tooth model.

Length measurements and descriptive characterizations were previously the sole reference points for describing the morphology of the occlusal surface. For computerized methods in dentistry, this is not sufficient for producing a data record. So far, the literature has reported no solutions. With the aid of a tooth library containing three-dimensionally measured occlusal surfaces free of caries and abrasion, a mathematical model was produced to describe a certain type of tooth by reference to a few parameters, taking account of functional and biologically relevant structures. This biogeneric tooth model was tested on 27 different inlay situations. The results show that fully automatic reconstruction was possible in all cases. The deviations of the reconstructions from the original tooth surface were on average around 150 microm. Furthermore, the influence of different parameters on the mathematical model was examined. Here, combinations that guarantee the best possible reconstruction for many situations could be found. The visual evaluation and the metric comparison of the reconstructions among one another illustrate the great flexibility of the biogeneric tooth model. With the aid of the biogeneric tooth model, there is the possibility of reconstructing the occlusal surfaces of dental restorations by CAD/CAM processes fully automatically, taking account of morphological and functional criteria. Further studies are needed to show to what extent the inclusion of degree of abrasion, antagonist and adjacent teeth delivers the desired results in the whole spectrum of clinical cases.

Computer Graphics↗

Relationships between fatty acids and psychophysiological parameters in depressive inpatients under experimentally induced stress.

Fatty acids can influence important cellular and hormonal processes in the human body. Non-adequate contents of fatty acids, e.g., in blood, can cause and/or result in various diseases. In depressive patients, changes in fatty acid concentrations were found (deficits in omega3-fatty acids, in particular). This paper poses the question whether there are any relations between psychophysiological parameters and changes in fatty acid compositions. The concentration of fatty acids in serum of 118 psychiatric inpatients measured directly before and after experimentally induced stress of about 1h were analysed in relation to psychophysiological parameters continuously registered during the experimental sessions at admission, discharge and at 3 months follow-up. Systolic and diastolic blood pressure, finger pulse amplitude, forehead temperature (FD) and the EMG activity of the musculus zygomaticus consistently correlated with concentrations of single unsaturated oleic (18:1n-9) and erucic acid (22:1) and saturated myristic (14:0) and lauric acid (12:0). Negative relations were found between FD and the concentration of arachidonic acid (20:4n-6) as well as of palmitoleic acid (16:1). Furthermore, the higher the concentration of the erucic acid at discharge the higher the depression score as assessed by the Beck depression inventory (BDI). High concentrations of palmitoleic acid and lauric acid were related to a low level of depression (BDI and Hamilton scores). The implications of these findings for add-on treatment regimens in depression are discussed.

Blood Pressure↗

[Recurrent strongyloidiasis as an indicator of HTLV-1 infection].

HISTORY AND CLINICAL FINDINGS: A 53-year-old West African man presented two years after a travel to Guinea because of severe headache, neck stiffnes, fever and pruritus. The patient had been in orthopedical treatment for the last five months. INVESTIGATIONS: Stool microscopy revealed a high number of Strongyloides stercoralis larvae. Hematology, biochemistry and all other parasitology results were normal. HIV-1/2 testing was negative and CD4+-lymphocyte count was normal. Concomitant infection by Human T Cell lymphotropic virus type 1 (HTLV-1) was confirmed by serology and PCR. The phylogenetic analysis confirmed African origin of the virus. TREATMENT: The infection responded to a five-day course of albendazol at 400 mg/d but during the following five years repeat recrudescences were observed inspite of high-dosage and prolonged antiparasitic treatments. Eventually, eradication of the infection was achieved by a four day course of ivermectin 0.2 mg/kg/d. CONCLUSIONS: Although both strongyloidiasis and HTLV-1 infections occur most frequently in tropical areas, these may also be observed in temperate regions. Suppression of the immune system by HTLV-1 differs from that by HIV. CD4+-lymphocytes were rarely decreased. Prolonged treatment with ivermectin in a dosage exceeding the current recommendations may be required in HTLV-1 infected patients and was well tolerated. The unusual presentation of the infection with muscular symptoms contributed to the delay of the diagnosis. HTLV-1 positive patients must be monitored for years. They and their partners must be instructed how to prevent transmission of the virus.

Albendazole↗

[Lupus in Germany: analysis within the German lupus self-help organization (LULA)].

During the last few decades, the prognosis for patients with systemic lupus erythematosus (LE) has changed from high early mortality to a more chronic longterm course. Although the prevalence of LE has been estimated at 20-50/100,000, data concerning the situation of LE patients in Germany are sparse. Since 2001, a documentation within the German Lupus Self-Help Organisation scheduled for a period of 10 years (LULA) has been recording at the patient level the actual status and the long-term course of a large group of LE patients. A questionnaire adapted from the German rheumatological database is updated once a year and sent to all members.In 2001, 1033 members participated in the documentation. Of these, 92.2% were women (mean age 45.8 years) with a mean disease duration of 9.9 years. 37.6% were employed, and 24.5% were on early retirement. 50.2% rated their overall health status as "not so good" or "poor". Most were receiving treatment with [hydroxy-]chloroquine (35.2%) or azathioprine (21.9%), while 67.9% were receiving corticosteroids. The most frequent comorbidities reported were hypertension (33%), scarring skin disease (24.4%), osteoarthritis (25.2%), osteoporosis (24%), psychiatric disorders/depression (22.9%) and chronic renal disease (22%). Thromboembolic events were reported in 18.5%, myocardial infarction in 2.3% and stroke in 4.8% of cases. Concerning their main contact person for health care, 63.6% specified the rheumatologist. In comparison with other cohort studies and in particular with the German rheumatological database, the data provided exclusively by patients are feasible. Concerning the severity of their disease, their treatment and their global assessment of health status, LULA participants are comparable with other LE patients and can be seen as representative of LE patients in Germany. Further assessment especially of long-term data are needed to obtain additional insights into the burden of the disease and the need for special medical care.

Adult↗

Electron microscopy and microcalorimetry of the postnatal rat heart (Rattus norvegicus).

The interplay of ultrastructure and tissue metabolism was examined in neonatal, infant and adult rat hearts by electron microscopy and microcalorimetry. Morphometry was used to determine parameters of oxygen diffusion capacity (distance between capillaries and mitochondria, capillary surface density) and oxidative metabolic capacity (mitochondrial volume fraction). Thin slices and large samples of living tissue were examined calorimetrically to quantify aerobic metabolism and ischemia tolerance, respectively. After birth, rat hearts grow in parallel to body mass and show characteristics of cellular hypertrophy. Capillary surface density increases from neonatal to infant rats, and decreases to an intermediate value in adult rats. The distance between capillaries and mitochondria shows no significant changes throughout postnatal development. Mitochondrial volume fraction increases continuously until adulthood. The specific aerobic tissue metabolic rate is higher in the neonatal than in the infant and adult rat. However, the ischemic decline in metabolic rate is much slower in the neonatal rat, reflecting an elevated hypoxia tolerance. In conclusion, the neonatal rat heart exhibits a high metabolic rate despite a low mitochondrial volume fraction. The subsequent structural rearrangements can be interpreted as long-term adaptations to the increased postnatal workload and may contribute to the progressive loss of hypoxia tolerance.

Aerobiosis↗

Long-term survival of patients with resistant lymphoma treated with tandem stem cell transplant.

Dose-intensive chemotherapy with autologous stem cell support is commonly used in resistant/refractory cases of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). The purpose of this study was to evaluate the role of tandem transplantation in these patients. We used non cross-resistant conditioning regimens with thiotepa, mitoxantrone and carboplatin (TMJ) followed by ifosphamide, carboplatin and etoposide (ICE) with autologous stem cell rescue in an attempt to maximize dose intensity and achieve long-term remission. Seventy-six patients were included in this study. Twenty-nine patients with HD and 47 with NHL underwent autologous stem cell transplant using TMJ as the conditioning regimen for the first transplant. Of these, 49 patients proceeded to the second transplant using ICE as the conditioning regimen. In 57 patients, only peripheral blood cells were used and in 11 patients both bone marrow and peripheral stem cells were used. Twelve patients died due to treatment-related toxicity. On an intent to treat basis, 32.14% of patients with HD refractory to initial or subsequent therapy survived long term as opposed to 12.76% of patients with NHL. With a median follow-up of 83 months (range 25 - 110 months), the median disease-free survival of patients with HD was 7 months, as opposed to 2 months for patients with NHL. Multivariate analysis identified that patients with HD had a superior outcome if they were less than 35 years of age and did not have B symptoms. Dose-intensive chemotherapy with tandem transplantation is an option in patients with resistant/refractory lymphoma who have very limited treatment options and poor prognosis.

Adult↗

MMPI-2 subgroups in a sample of chronic pain patients.

MMPI-2 scores of 307 female and 161 male chronic pain patients were analyzed by gender using a multivariate clustering method. Two subgroups were found for both sexes replicating previous results. The major subgroup corresponded to the classical "Conversion V" and the minor corresponded to the "Generally elevated" profile. The results also indicated a satisfactory internal consistency and a high discriminant validity of the Swedish version of the MMPI-2.

Case-Control Studies↗

Alveolar nitric oxide in adults with asthma: evidence of distal lung inflammation in refractory asthma.

Recent studies have suggested that alveolar nitric oxide (NO) concentration is a noninvasive test of distal lung inflammation. The current study determined whether alveolar NO concentration can be measured in patients with asthma of varying severity, tested the hypothesis that there is an association between alveolar NO and bronchoalveolar lavage (BAL) eosinophil count and determined whether refractory asthma is characterised by a raised alveolar NO concentration. Finally, the present authors assessed the effect of 2 weeks of prednisolone (30 mg q.d.) on alveolar NO concentration. Alveolar NO concentration was both measurable and repeatable in patients with refractory asthma. A positive correlation was found between alveolar NO concentration and BAL eosinophil count but not with bronchial wash or sputum eosinophil count. Alveolar NO concentration was increased in patients with refractory asthma (7.1 ppb) compared with mild-to-moderate asthma (3.4 ppb) and normal controls (3.4 ppb) and reduced by treatment with prednisolone. In conclusion, these findings support the hypothesis that alveolar nitric oxide is a measure of distal airway inflammation and suggest that distal lung inflammation is present in refractory asthma.

Administration, Inhalation↗