Biomedical subjects
Publications and source records attributed to M Lucht.
We demonstrate an interferometer for hard x rays with two back-reflecting sapphire crystal mirrors--a prototype x-ray Fabry-Pérot interferometer. A finesse of 15 and 0.76 mu eV broad Fabry-Pérot transmission resonances are measured by the time response of the interferometer. Interference patterns are observed directly in spectral dependences of reflectivity.
The difference Delta(a)=a(30)-a(28) of the lattice parameter of 30Si and 28Si crystals is measured over a temperature range from 4.7 to 700 K. In disagreement with existing knowledge, the strongest isotopic effect is not detected at the lowest achieved temperature T=4.7 K. An anomalous behavior is observed: The relative difference |Delta(a)/a| attains its maximum value of 56.8(5) ppm at T=75(10) K. The anomalous behavior is attributed to the influence of phonon modes with negative Grüneisen parameters. At T=700 K the effect still amounts to 30% of the maximal value. The experimental data are consistent with an approach based on the density-functional perturbation theory.
In earlier studies, children of alcoholics (COAs) reported more alcohol and drug problems and higher levels of maladaptive behaviour and psychiatric distress than non-COAs. However, increased exposure to drugs and alcohol among COAs does not fully explain this phenomenon. In our family-based study design, we were able to investigate specific risk factors for alcohol problems in adolescence. In a first step, we compared a variety of psychosocial risk factors in 90 adolescents (12-18 years of age) from families with at least one alcohol-abusing parent with those of 90 adolescents of parents without alcohol disorders. In a second step, we investigated the meaning of all included risk factors for alcohol problems of the adolescents. Our results give some support to the existence of a lower extent of emotional warmth and support by parents of children in the COA sample. Moreover, males of the COA group reported more parental rejection and higher values on measures of attention problems and anxiety/depression than controls, whereas there were no such differences between females of the COA group and their control counterparts. Additionally, logistic regression analysis revealed that only the membership in a substance-using peer group and higher age are important risk factors for alcohol problems during adolescence. Considering our results, it is of great importance (a) to identify families at risk at the earliest possible stage and (b) to develop intervention and prevention programs further for parents and children to increase social competence and protect children at risk from later alcohol abuse.
We tested the use of some subscales of the psychiatric symptom checklist SCL-90-R in predicting relapse within a 1-year follow-up period after a combined detoxification- and abstinence-focused day patient psychotherapy program in 20 men and 13 women with alcohol dependence. Scores of the SCL-90-R subscales interpersonal sensitivity (p = 0.008), anxiety (p = 0.022), phobic anxiety (p = 0.019) and Global Severity Index (GSI; p = 0.040) on admission were higher in the subgroup with relapse within the first year after therapy. A decrease in depression (p = 0.004), anxiety (p = 0.006) and GSI (p = 0.006) scores during therapy was associated with a longer abstinence duration (shorter vs. longer than 24 weeks). Therefore we propose to further investigate the capacity of the SCL-90-R to identify subgroups at higher risk for relapse after detoxification and abstinence therapy in patients with alcohol dependence.
The wavelength of the 57Fe Mössbauer radiation is measured with a relative uncertainty of 0.19 ppm by using almost exact Bragg backscattering from a reference silicon crystal. Its value is determined as lambda(M) = 0.860 254 74(16)x10(-10) m. The corresponding Mössbauer photon energy is E(M) = 14 412.497(3) eV. The wavelength of the 57Fe Mössbauer radiation is easily reproducible with an accuracy of at least 10(-11)lambda(M) and could be used as a length standard of atomic dimensions.
The effect of the ATP-inhibited K+ channel on the membrane potential of leech Retzius neurons was analyzed using electrolyte-filled single-barrelled microelectrodes. The membrane potential was independent of the external nutrient supply during a period of 11 h, probably because the internal energy reserves were sufficient. The K+ channel activator HOE 234 ((3S,4R)-3-hydroxy-2, 2-dimethyl-4-(2-oxo-1-pyrrolidinyl)-6-phenylsulfonylchromane hemihydrate, 500 microM) induced a membrane hyperpolarization. In the presence of HOE 234, action potentials occurred with a reduced after-hyperpolarization and were discharged in bursts, possibly because of an inhibition of Ca2+ channels. The blocker of ATP-inhibited K+ channels tolbutamide did not significantly alter the membrane potential. In the absence of tolbutamide, the metabolic inhibitors iodoacetate, azide and cyanide (10 mM) evoked membrane hyperpolarizations, but in the presence of 1 mM tolbutamide their hyperpolarizing actions were reduced or abolished while membrane depolarizations were intensified. We conclude that ATP-inhibited K+ channels in the soma membrane of leech Retzius neurons provide coupling of cellular metabolism to electrical activity and ionic fluxes.
Partial sleep deprivation (PSD) results in a pronounced decrease of depressive symptoms in the majority of patients with major depressive disorder. Generally this acute antidepressant effect is not stable, relapse usually occurs after one night of recovery sleep. We therefore studied whether light therapy, beginning in the morning after PSD, is able to prevent the relapse after sleep deprivation, using a controlled, balanced, parallel design. All patients received an antidepressant medication, which was kept constant before and during the study period. Fourteen of 20 patients (70%) showed a reduction of at least 40% in the Hamilton Depression Rating Scale (HDRS) in the morning after PSD and were classified as PSD responders. Responders as well as nonresponders were randomly assigned to receive either bright light (BL/3000 lux) or dim light (DL/100 lux) therapy during the following 6 days after PSD. In the responder group BL therapy prevented significantly (p = 0.005) the relapse after the next night of sleep and prolonged significantly (p = 0.011) the antidepressant effects of PSD up to 7 days. In contrast, patients in the DL condition relapsed after the recovery night and showed no further improvement of the depressive syndrome after 1 week of DL therapy. PSD nonresponders did not benefit from light treatment. These findings indicate that BL therapy might be efficacious to prevent relapse after PSD.
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Proprioceptive sensibility from stimulation of muscle, ligament articular and vestibular receptors plays a determining role in the regulation of tone, of the resting position of the mandible, of head posture and of the closure pathway of the mandible. Studies conducted on temporomandibular joints of fetuses and adult subjects failed to demonstrate the specialized corpuscles (a fact previously noted by Ramfjord) in the temporomaxillary joint capsule, described typically in other joints. In contrast, however, histology showed a particularly rich population of muscle receptors adjacent to this joint, this being only one of several particular characteristics.
In this study, 57 women were examined in terms of the influence of different psychosocial factors on their subsequent mental well-being and physical complaints one day before, one day after, and 3 months after undergoing an in-patient abortion. Furthermore a control group of 40 in-patients (women with pregnancy related problems) were included in the study. The results show that prior to the abortion, most women reported a multitude of psychological and physical problems. However, it was also shown that for the majority of the women interviewed, mental well-being and physical complaints improved significantly one day and 3 months after the abortion. While feelings such as relief predominated immediately postoperatively, after 3 months, participants reported feeling cheerful and interested in activities. Further, it was demonstrated that women whose general mood was more pronouncedly anxious-depressive one day prior to operation later (after 3 months) reported many complaints and worse well-being. It appears that these women were not able to experience the abortion as a problem solutions. Finally, the great importance of the quality of their relationship and cohesion was demonstrated in the decision to abort, while pregnancy counselling was found to have no effect.
AIMS AND METHODS: Alcohol withdrawal treatment efficacy of tiapride/carbamazepine (A) vs clomethiazole (B) vs diazepam (C) in non-intoxicated patients and vs tiapride/carbamazepine in intoxicated patients (D; breath alcohol concentration > or = 1 g/l) was tested (n = 127) in a controlled randomized open-label study. RESULTS: Efficacy and safety were not different between groups (total group: delirium, 3.9%; seizure, 0.8%), except for a lack of efficacy in 18% of intoxicated tiapride/carbamazepine patients. A change of medication in this group was necessary only when primarily intoxicated patients had reached the non-intoxicated range. CONCLUSIONS: Treatment with tiapride/carbamazepine in alcohol-intoxicated patients proved to be safe.
The results of this study provide evidence for the importance of psychosocial risks in childhood for aggressive behavior in adolescence. This study demonstrated that aggressive adolescents differed from a nonaggressive control group in an increased exposure to prior psychotraumatic events, such as sexual abuse (tendency), physical abuse, and broken homes. However, in predicting later aggressive behavior, long-term and chronically effective negative living conditions seem of greater importance. Parenting behavior which includes harsh punishment and emotional rejection as well as separation of the parents early in life are particularly important factors. Whereas aggressive girls do not differ from the nonaggressive control group in terms of self-reported mental health, the aggressive boys reported more attention deficits, depression, anxiety, delinquency, and social problems.