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Biomedical subjects

J Dittmann

Publications and source records attributed to J Dittmann.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Leukocyte filtration of stored whole blood for preparation of components].

Prophylaxis of infection and alloimmunisation is the main reason for leucocyte depletion by filtration of blood components. The question is whether all red cell concentrates (RCC) should be filtered and whether plasma has to be filtered, too. For leucocyte-poor units whole blood was filtered before preparation using the 'top and bottom' system. These units of buffy-coat-poor RCC and plasma were compared with components filtered after preparation. Non-filtered RCCs and plasmas served as a control. By prefiltration of whole blood and filtration of components we obtained RCCs and plasmas with less than 1 x 10(5) leucocytes in every unit. In conclusion, leucocyte filtration before preparation seems to be an easy and cost-effective method in order to get two filtered components (RCC and plasma) with one filter.

Blood Component Transfusion↗
PubMed1994

[Platelet membrane glycoproteins in thrombocytapheresis and platelet concentrates].

Membrane glycoprotein (GP) expression on platelets changes during preparation of concentrates and storage. Recent studies proved that the increased expression of the GMP-140 (CD 62), a GP appearing on platelets after activation, correlates with the in vivo recovery of transfused platelets. We therefore investigated the expression of this and three other GP (GP IIb/IIIa, GP, Ib, GP 53), detected by flow cytometry, in normal controls and in platelet concentrates prepared by four different methods (apheresis, preparation from buffy coat, from pooled buffy coat and platelet-rich plasma) after preparation and during storage. Furthermore we investigated the influence of filtration, radiation and washing platelet concentrates on the expression of GP. The results can be summarized as follows: (1) The mean surface fluorescence (MF) is a better parameter for the evaluation of preparation and storage lesions than the total number of positive cells. (2) The mean fluorescence of GP Ib in platelet concentrates is generally lower than in normal controls and decreases continuously during storage; there is a small loss of GP Ib through washing and filtration. (3) GP IIb/IIIa fluctuates during preparation and storage, therefore it is not suitable for evaluation of quality. (4) The percentage of CD 62 positive cells and their mean fluorescence is higher in platelet concentrates than in normal controls and increases during storage continuously. There is a weak correlation of CD 62 with CD 63. (5) The changes of GP in apheresis concentrates and concentrates obtained from whole blood are similar after preparation and during storage.

Blood Platelets↗
PubMed1993

[Different effects of homeopathic potencies and conventional dilutions on specific liver enzymes of rats--an in vivo study].

It was searched for differing effects of homeopathic potencies and equally concentrated conventional dilutions. Activities of enzymes from three different subcellular compartments of the rat liver served as parameters for the evaluation. Especially in the D15/10(-15) range differences proved to be statistically relevant. The series with potentiated carrier substance, necessary from heuristic reasons and related to the homeopathic potencies, resulted in hitherto not understandable findings.

Acetylglucosaminidase↗
PubMed1992

Enzymatic biosynthesis of cyclosporin A and analogues.

The final assembly of the undecapeptide chain of cyclosporin A and its cyclization is accomplished in Beauveria nivea by cyclosporin synthetase. This multienzyme is the largest integrated enzyme structure so far reported. Its size has been estimated at approximately 1,400 kDa by two different methods: 1), by 3% SDS-PAGE using the related multienzymes ACV synthetase and gramicidin S synthetase 2 as references (420 and 556 kDa, respectively); and 2), by CsCl density gradient centrifugation experiments using fluorescence-labeled cyclosporin synthetase. Besides cyclosporin A and a number of cyclosporins known from fermentation studies cyclosporin synthetase is capable of synthesizing some new cyclosporins which are so far unobtainable by fermentation. So, for example the synthesis of [N-methyl-(+)-2-amino-3-hydroxy-4,4-dimethyloctanoic acid1]CyA, dihydro-CyA, [L-norvaline2,5, N-methyl-L-norvaline11]CyA, [L-allo-isoleucine5, N-methyl-L-allo-isoleucine11]CyA, [D-2-aminobutyric acid8]CyA, [beta-chloro-D-alanine8]CyA and some related compounds could be established. By using a related but different enzyme from Cylindrotrichum Bonorden, the peptolide [L-threonine2, L-leucine5,10, D-2-hydroxyisovaleric acid8]CyA could be synthesized in vitro. We were able to synthesize these cyclosporins in sufficient quantities to examine their structure by FAB mass spectroscopy and explore their immunosuppressivity. It was found that all new cyclosporins so far synthesized in the in vitro system are immunosuppressive.

Amino Acid Sequence↗
PubMed1992

[Coping and compensation strategies of patients with disseminated encephalomyelitis and of patients with schizophrenic psychoses].

In ten patients with schizophrenic psychosis and ten patients with multiple sclerosis, the coping and compensation strategies were examined by means of semistructured interviewing. The following categories were considered: 1. avoidance; 2. habituation and/or adaptation to the disease; 3. efforts to compensate the deficits by will-power; 4. efforts to train certain types of behaviour; 5. self-treatment; 6. disease awareness and insight. Examples for these categories are given for both groups of patients. There is a surprising similarity in the statements made by the schizophrenic patients and those with multiple sclerosis. All of the patients with multiple sclerosis had developed coping strategies against psychological symptoms. It is suggested that the neuropsychological deficits in multiple sclerosis resemble the symptoms of reduced energetic potential observed in schizophrenia. In both groups efforts should be made to activate the compensation strategies by adequate training procedures.

Adaptation, Psychological↗
PubMed1991

Different regulation of adrenocorticotropin and cortisol secretion in young, mentally healthy elderly and patients with senile dementia of Alzheimer's type.

Previous studies suggest that an alteration of the neuroendocrine system may particularly occur in senile dementia of Alzheimer's type (SDAT). In the present study the reactivity of the hypophyseal-adrenocortical axis (HPA) in the elderly was assessed by hormonal stimulation of the hypophysis. Twelve young men (aged 21-24 yr), 15 mentally healthy elderly (aged 65-90 yr), and 12 patients with SDAT (aged 60-84 yr) received an iv bolus injection containing 50 micrograms CRH and 0.5 IU lysine vasopressin after a baseline period of 2 h. ACTH, cortisol, and dehydroepiandrosterone secretion was monitored over a period of 2 h before and after the injection. The baseline ACTH concentrations were increased in both groups of elderly, the baseline cortisol levels were not different in either group. The peak ACTH and cortisol levels were significantly elevated in the mentally healthy elderly, whereas senile demented patients showed a rise comparable with that in the young subjects. Moreover, in the demented patients the post-stimulus decline in plasma ACTH levels seemed to be delayed. Dehydroepiandrosterone was significantly lowered in subjects of all ages. Our results demonstrate an enhanced reactivity of the HPA in mentally healthy elderly. This is possibly due to a diminished sensitivity of the feedback regulation to glucocorticoids. However, SDAT patients had, compared to healthy elderly subjects, an attenuated response to CRH/lysine vasopressin and a prolonged ACTH secretion, indicating alterations of the HPA in this disease.

Adrenocorticotropic Hormone↗
PubMed1991

Cell-free biosynthesis of cyclosporin A and analogues.

The final assembly of the 11-peptide chain of cyclosporins and its cyclization is accomplished in the producer Beauveria nivea by cyclosporine synthetase. This multienzyme represents the largest integrated enzyme structure reported so far. Its size has been estimated to approximately 1,500 kDa by SDS-PAGE. Some enzyme bound linear peptides could be isolated and identified. All of them represent partial sequences of cyclosporin A starting with D-alanine. These peptides were bound by thioester linkage to the enzyme. This could be demonstrated by liberation of the peptides with performic acid and by inhibition of in vitro cyclosporin A synthesis with thiol blocking agents. Cyclosporin synthetase is capable to synthesize besides a lot of cyclosporins known from fermentation studies some new cyclosporins so far not obtainable by fermentation. So, for example the synthesis of [N-methyl-(+)-2-amino-3-hydroxy-4,4-dimethyloctanoic acid1]CyA, Dihydro-CyA, [L-norvaline2,5, N-methyl-L-norvaline11]CyA, [L-allo-isoleucine5, N-methyl-L-allo-isoleucine11]CyA, [D-2-aminobutyric acid8]CyA, [beta-chloro-D-alanine8]CyA and some related compounds could be established. We were able to synthesize these cyclosporins in sufficient quantities to ensure their structure by fast atom bomdardment mass spectroscopy and to examine their immunosuppressitivity. All new cyclosporins synthesized in the in vitro system so far are immunosuppressive.

Amino Acid Sequence↗
PubMed1990

[Autoprotective mechanisms in patients with schizophrenic psychoses--compensation and coping].

For a long time, the coping and compensatory mechanisms of patients with schizophrenic psychoses have mostly been neglected by the psychiatric research. We extended the six categories of coping mechanisms described in the Bonn Scale for the Assessment of Basic Symptoms (BSABS) by three further categories. With fifty schizophrenic patients in different stages of their disease semistructured interviews concerning these categories were done. The main sociodemographic and historical parameters were registered as well. Then the protocols of the interviews were analyzed, the coping strategies were quantified, and it was tried to disclose relations between the disease progress and sociodemographic parameters. Patients used to a certain degree of autonomy e. g. unmarried patients had--compared to less independent patients--stronger coping strategies. Patients with a strong interest for their disease and a positive opinion about neuroleptic therapy had--compared to patients without interest for their disease and/or negative opinion about neuroleptic therapy--stronger coping and compensatory psychisms. It is concluded that the coping strategies might be reinforced by influencing these parameters.

Adaptation, Psychological↗
PubMed1990

Disease consciousness and coping strategies of patients with schizophrenic psychosis.

In 50 schizophrenic patients, semistructured interviews were carried out concerning disease consciousness, occupation with the disease and behaviour and coping in case of psychotic experiences; 72% of the patients occupied themselves with their disease. In 84% a disease consciousness was present; 38% gave a multifactorial explanation for their psychosis. In 94% the occasional appearance of psychotic experiences was acknowledged. In 86% specific changes of the individual behaviour for coping with these experiences were described. These changes included withdrawal, increasing of interpersonal contact, cognitive control, symptomatic behaviour and adjustment of the neuroleptic medication. The study shows that schizophrenic patients are not passive victims of their disease. In the majority of cases a disease consciousness is present. The patients try to cope with their psychotic experiences in individually different ways. It is assumed that a better knowledge of these strategies might enable the clinician to use these phenomena as an adjunct to pharmacotherapy.

Adaptation, Psychological↗
PubMed1990

Isolation and partial characterization of cyclosporin synthetase from a cyclosporin non-producing mutant of Beauveria nivea.

Cyclosporin synthetase was isolated from a cyclosporin non-producing mutant of Beauveria nivea, strain YP 582. The enzyme has a molecular mass in the range of active cyclosporin synthetase and also contains 4'-phosphopantetheine as a prosthetic group. It is able to activate all constituent amino acids of cyclosporin A as thioesters and to carry out specific N-methylation reactions. Overall synthesis of the undecapeptide cyclosporin A in the presence of all necessary substrates was not observed, but the formation of the diketopiperazine cyclo-(D-alanyl-N-methyl-leucyl). This diketopiperazine represents a partial sequence of the cyclosporin molecule. It could be detected in the mycelium of the non-producing strain, whereas mycelium of the producing strain 7939/45 did not contain this compound. The results suggest that the inability of this mutant to produce cyclosporin A is caused by a mutation of the polypeptide chain of cyclosporin synthetase.

Amino Acid Sequence↗
PubMed1989

[Coping and psychological compensation in patients with endogenous psychoses of schizophrenic origin].

For a long period of time, the coping and compensatory mechanisms that arise from the patients with schizophrenic psychoses themselves have been considered only to a small extent by the psychiatric research. On the basis of Huber's concept of basic symptoms, we extended the six categories of coping mechanisms which are described in the Bonn Scale for the Assessment of Basic Symptoms (BSABS) by three further categories. With ten schizophrenic patients - mostly in-patients - semistructured interviews concerning these categories were done. All patients were found to have coping and compensatory mechanisms, and as a contribution to recognize and describe these mechanisms, parts of the patients' remarks are quoted. This is a prerequisite for an operationalized recording on larger patient populations that will possibly also allow correlation-statistical conclusions.

Adaptation, Psychological↗
PubMed1979

Sodium nitroprusside (NPS) stimulates the lactate formation and causes intracellular electrolyte shifts in brain slices.

Nitroprusside sodium (NPS) was added to slices from grey and white rabbit brain matter. The respiration, consumption of glucose, formation of lactate and pyruvate, water content, size of the extracellular space, and total and intracellular sodium and potassium concentrations were determined and calculated. 0.5 and 1 mM NPS stimulated the glycolytic glucose breakdown, and inhibited the respiration of grey and white slices. The respiration of white matter slices was stimulated by 0.05 and 0.01 mM NPS. The total and intracellular potassium concentrations in slices from grey and white matter were lowered markedly by 1 mM NPS. The total and the intracellular sodium concentrations in grey brain matter slices became higher in the presence of 1 mM NPS. A warning is given against uncritical clinical use of higher concentrations of NPS.

Animals↗
PubMed1975

Advantage of defined tissue slices against minced samples in biochemical in vitro investigations of brain cortex.

A cutting device for the preparation of brain cortex slices with a regular cylindric shape and a defined thickness is described. Determinations of the glucose and the electrolyte metabolism and the reactions of both to substances' additions were made with minced brain and with brain slices of different thichknes. The comparison of the methods and of the results makes evident that experimentation with slices has several advantages.

Animals↗