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Biomedical subjects

A Fischer

Publications and source records attributed to A Fischer.

At least 181 records · Page 10Linked to original sources
PubMed2000

[Schizophrenic psychoses and suicide in the clinic. Risk factors, psychopharmacologic treatment].

For all 5,352 patients treated for schizophrenia at the Psychiatric Hospital of the University of Munich in 1981 and 1992, detailed routine and data processing-assisted documentations were made of the psychopharmacological therapies. Nineteen of the patients committed suicide while undergoing inpatient treatment; the control group consisted of all other patients (n = 5,333). More than 77 sociodemographic and anamnestic variables as well as 195 items from the admission summaries were taken into account while comparing the groups. Furthermore, the pharmacological data were classified according to drug groups and comparison was based on the mean frequency of prescription of each group. We analyzed the mean number of prescriptions for neuroleptics, tranquilizers, and antidepressants, which were further differentiated into sedating and nonsedating types. For frequently administered drugs, mean daily doses were also compared. Bivariate analysis of the data suggests that the suicide cases presented depressive signs, symptoms, and tendencies already present on admission more frequently than with controls; the same applies to previously attempted suicides. Discriminating analysis showed that the variables "feeling of loss of feelings," thought insertion," "visible depression," "free-floating anxiety," "suicidal tendencies," and "previously attempted suicide" have the greatest predictive value with respect to suicide, in descending order. No differences in psychopharmacological treatment between suicides and controls were found, apart from a significantly higher percentage of antidepressive treatments and a higher mean number of antidepressant prescriptions for the suicides.

Adult↗
PubMed2000

Phenylacetylene as a new surrogate standard for the determination of BTEX by GC/FID.

Benzene, toluene, ethylbenzene, xylene (short form: BTEX) and other monoaromatic compounds are environmental contaminants which are often analyzed by GC/FID. For the calculation of BTEX concentrations in water samples normally external quantification with defined BTEX solutions is sufficient. However, for accurate quantification of BTEX in complex matrices it is necessary to use internal standards, e.g. 1-chlorohexane. Isotopes of BTEX are usually the best alternative but they are only applicable to GC/MS, because their retention times are similar to the original BTEX. 1-Chlorohexane and phenylacetylene were compared with respect to their quality as internal standards. Good results were obtained with the monoaromatic phenylacetylene as a surrogate standard. The physical properties of phenylacetylene are very similar to BTEX species and it normally does not occur in environmental samples. 1-Chlorohexane was more strongly adsorbed on the used soil than BTEX during sample preparation. This fact suggests that the single aromatic rings of BTEX and phenylacetylene are mainly responsible for the adsorption behavior.

Acetylene↗
PubMed2000

Founder effect for a 26-bp deletion in the RFXANK gene in North African major histocompatibility complex class II-deficient patients belonging to complementation group B.

Expression of major histocompatibility complex (MHC) class II genes is controlled at the transcriptional level by at least four trans-acting genes, CIITA, RFXANK, RFX5, and RFXAP. Defects in these regulatory genes result in the absence of MHC class II molecule expression and, thereby, cause a combined immunodeficiency. MHC class II deficiency is inherited as an autosomal recessive trait. Since the first description of the disease, about 70 patients from 50 families have been reported. Forty-three of these families have been classified into four complementation groups: A, B, C, and D. In the largest group, B, the majority of patients are of North African origin. In two of these patients, the same mutation in the RFXANK gene (752delG-25) was identified. We performed a mutation analysis in 20 additional patients belonging to complementation group B and detected the 752delG-25 mutation in 17. All of these patients are of North African origin. A founder effect for this mutation was documented, since all tested patients, except one, display a common haplotype spanning the RFXANK locus.

Africa, Northern↗
PubMed2000

[Biophysical study of coronary stents: which factors influence the dilatation and recoil behavior?].

In Europe more than fifty stents are currently available for the therapy of coronary artery disease. Nonetheless it is unknown whether material and design influence the stent's behavior. We have studied the recoil and dilatation behavior of five currently available stainless steel (316L) stents compared to stent prototypes made of pure titanium. Furthermore we have investigated how the behavior is influenced by the process of crimping. The aim of this work was to determine material and design characteristics, which influence the recoil and dilatation behavior. The 316L stents showed a homogeneous behavior (plateau pressure min. 1.15 +/- 0.01 atm, max. 0.26 +/- 0.03 atm, recoil min. 0.15 +/- 0.03%, max. 0.26 +/- 0.03%). The titanium stent showed a linear response to the balloon expansion. This was seen in a significantly lower plateau pressure (0.43 +/- 0.15 atm, p < 0.001). Despite the material characteristics of titanium, there were no significant differences in the recoil behavior (0.28 +/- 0.02%). Crimping leads to stent alterations which result in a significantly higher plateau pressure (1.9 +/- 0.07 atm vs. 2.7 +/- 0.58 atm, p < 0.001) and a reduced end-diameter (3.6 +/- 0.02 mm vs. 3.54 +/- 0.05 mm, p < 0.005). The presented data show that the dilatation behavior is relying on the stent material while the recoil is strongly influenced by the stent design.

Angioplasty, Balloon, Coronary↗
PubMed2000

Nociceptin effects in the airways.

The opioid-like heptadecapeptide nociceptin (NC) has the following effects in the airways (investigated in isolated tracheae and bronchi from guinea pig or rat): the electric field stimulation (EFS)-induces release of acetylcholine (ACh), the tachykinin substance P (SP) and calcitonin gene-related peptide (CGRP) is reduced after pretreatment with NC, and EFS-induced tachykinergic nonadrenergic-noncholinergic (NANC) bronchoconstriction is inhibited by NC. Both the NC-mediated inhibition of neurotransmission and of smooth muscle contraction occurred in a concentration-dependent manner. Because these effects were naloxone-insensitive, were blocked by the NC receptor antagonist [F/G]NC(1-13)NH(2), and could be mimicked by the NC analogs, NCNH(2) and NC(1-13)NH(2), it is thought that they are distinct from the classic opioid receptors. That these pharmacological actions of NC are of relevance for airway physiology is highly probable given the presence of NC-immunoreactivity in the nerve fibers of the airways and of opioid-like receptor (ORL-1) transcripts in the jugular ganglia, from where the tachykinin-containing afferents arise.

Acetylcholine↗
PubMed2000

Characterization of Klebsiella terrigena strains from humans: haemagglutinins, serum resistance, siderophore synthesis, and serotypes.

Klebsiella terrigena is very rarely isolated from humans; as yet, its clinical significance is uncertain. The aim of the present study was to evaluate whether this species is able to express putative virulence factors. A total of 72 faecal (n = 50) and clinical (n = 22) K. terrigena isolates was investigated and compared with faecal and clinical strains of K. pneumoniae. Mannose-sensitive haemagglutination (MSHA) was observed less often in K. terrigena (64-74%) than in K. pneumoniae strains. In contrast, the incidence of mannose-resistant haemagglutinin indicative of type 3 pili (MR/K-HA) (77-94%), serum resistance properties (10-23%), and production of enterobactin (100%) was similar in both species. None of the K. terrigena isolates were able to synthesize aerobactin; however, the frequency of aerobactin synthesis in K. pneumoniae was also only 5%. Serotyping showed capsular types K5 and K70 to be predominant. The virulence-associated serotype K2 was common in both K. terrigena and K. pneumoniae isolates. Taken together, the present results suggest that K. terrigena and K. pneumoniae are indistinguishable with respect to the expression of virulence factors.

Blood Bactericidal Activity↗
PubMed2000

The impaired immune response to diphtheria vaccination in elderly chronic hemodialysis patients is related to zinc deficiency.

Zinc deficiency causes abnormalities of the immune response. In chronic hemodialysis therapy abnormalities in zinc metabolism as well as an impaired immune response to vaccination have been reported. Therefore we performed a vaccination study against diphtheria and hypothesized that the response to diphtheria vaccination is related to serum zinc deficiency in hemodialysis patients. Serum zinc concentrations were assayed in 16 chronic hemodialysis patients (10 male, 6 female; mean age 65 years) without a documented vaccination history against diphtheria. Nine of these patients were triple immunized against diphtheria while seven received a single vaccination. The response to diphtheria vaccination was measured by ELISA detecting specific antibodies to diphtheria-toxoid. Seroconversion 6 and 12 months after vaccination was defined as the doubling of antibody titers in patients > or = 0.1 IU/ml prior to vaccination or as titers > 0.1 IU/ml in all other patients. Only 6/16 hemodialysis patients responded to immunization against diphtheria by specific antibody production (> 0.1 IU/ml). Twelve months after the single injection 3/7 patients seroconverted while six months after the triple vaccination 3/9 patients responded to immunization. This was not age-dependent, whereas in non-responders we detected significantly decreased serum zinc levels. In contrast, responders showed similar serum zinc levels as age-matched controls. Furthermore, we measured a decreased alpha 2-macroglobulin concentration only in the responders amongst the hemodialysis patients. Protection against diphtheria and the immune response to diphtheria vaccination in hemodialysis patients is poor. The failure to respond to active diphtheria vaccination is related to a significantly decreased serum zinc concentration in hemodialysis patients.

Aged↗
PubMed2000

Ticlopidine enhances the platelet inhibitory capacity of abciximab in vitro.

Ticlopidine and abciximab are two antiplatelet agents that are frequently administered during percutaneous coronary interventions. Although they have different mechanisms of action and pharmacological profiles, the two agents are often concomitantly used in complicated stent placements. The purpose of the study was to evaluate the effect of ticlopidine therapy on the capacity of abciximab to inhibit platelet aggregation, in vitro. Blood samples from 13 ticlopidine-treated stent placement patients and 8 patients undergoing PTCA who did not receive ticlopidine were obtained prior to, 12-36 hours and 7-10 days after initiating ticlopidine treatment. For each patient, the minimal ADP and the thrombin receptor activating peptide (TRAP) concentrations that elicited maximal platelet aggregation responses at baseline were used to measure the extent of platelet aggregation and the abciximab concentration that gave a 50% decrease in aggregation (IC(50)) for both agonists at the three time points. The ticlopidine group baseline and 12-36 hour mean ADP aggregation responses were equivalent, but decreased by 34% (P = 0.009) at 7-10 days. The control group ADP and TRAP, as well as the ticlopidine group TRAP aggregation responses, were equivalent at all time points. The ticlopidine group baseline and 12-36 hour abciximab IC(50) values for ADP were comparable (1.58 +/- 1.1 ng/mL vs. 1.23 +/- 0.5 ng/mL; P = 0.266), but decreased to 1.00 +/- 0.6 ng/mL (36%; P = 0.004) at 7-10 days. In contrast, the abciximab IC(50) for TRAP increased from 1.48 +/- 1.0 ng/mL to 1.85 +/- 1.1 ng/mL (25%; P = 0.033) at 12-36 hours, but returned to baseline at 7-10 days (1.40 +/- 0.8; P = 0.975). The control group IC(50) abciximab values for ADP and TRAP were comparable throughout the monitoring period. The results demonstrate that ticlopidine elicits subtle potentiation of the platelet-inhibitory capacity of abciximab to the agonist ADP, but not TRAP, at 1 week after initiation of treatment.

Abciximab↗
PubMed2000

Gene therapy of severe combined immunodeficiencies.

Primary immunodeficiency diseases (PID) are attractive candi dates for a gene therapy approach because many of these disorders convey a poor prognosis while a number of the genes mutated in these conditions have been identified. Gene transfer into hematopoietic stem cells (HSC) should, in theory, lead to a cure of the disease. There are, however, a number of limitations mostly related to the failure of clinically available vectors to enable transgene integration into HSC. Nevertheless PID due to a gene defect leading to failure of cell development could be amenable to gene therapy given the selective advantage conferred to transgene expression in progenitor cells. Terminally differentiated cells are, however, long lived, as is the case for T lymphocytes. This concept led to the first gene therapy trials for adenosine deaminase (ADA) deficiency several years ago. Results were in part disappointing mostly because of the concomitant substitutive treatment by polyethylene glycol-ADA. However, recent application to X-linked severe combined immunodeficiency (gamma(c) deficiency) turned out to be efficient at least on a relatively short term basis (i.e. one year so far). These results demonstrate that this concept is valid and can be the basis for the treatment of other forms of severe T-cell immunodeficiencies. Obviously, development of vectors (lentiviruses) able to efficiently target HSC could in the future considerably enlarge the field of PID treatable by gene transfer.

Animals↗
PubMed2000

Mutations in RAB27A cause Griscelli syndrome associated with haemophagocytic syndrome.

Griscelli syndrome (GS, MIM 214450), a rare, autosomal recessive disorder, results in pigmentary dilution of the skin and the hair, the presence of large clumps of pigment in hair shafts and an accumulation of melanosomes in melanocytes. Most patients also develop an uncontrolled T-lymphocyte and macrophage activation syndrome (known as haemophagocytic syndrome, HS), leading to death in the absence of bone-marrow transplantation. In contrast, early in life some GS patients show a severe neurological impairment without apparent immune abnormalities. We previously mapped the GS locus to chromosome 15q21 and found a mutation in a gene (MYO5A) encoding a molecular motor in two patients. Further linkage analysis suggested a second gene associated with GS was in the same chromosomal region. Homozygosity mapping in additional families narrowed the candidate region to a 3.1-cM interval between D15S1003 and D15S962. We detected mutations in RAB27A, which lies within this interval, in 16 patients with GS. Unlike MYO5A, the GTP-binding protein RAB27A appears to be involved in the control of the immune system, as all patients with RAB27A mutations, but none with the MYO5A mutation, developed HS. In addition, RAB27A-deficient T cells exhibited reduced cytotoxicity and cytolytic granule exocytosis, whereas MYO5A-defective T cells did not. RAB27A appears to be a key effector of cytotoxic granule exocytosis, a pathway essential for immune homeostasis.

B-Lymphocytes↗
PubMed2000

Changes in height, weight and plasma leptin after bone marrow transplantation.

Short stature can be a severe side-effect of bone marrow transplantation (BMT). Because of the effect of weight changes on growth rate and on plasma insulin-like growth factor (IGF I), we analyzed changes in height and body mass index (BMI) in 53 patients given BMT. Group 1 (n = 22) was given 12 Gy total body irradiation (TBI) as six fractions, group 2 (n = 14) 10 Gy TBI (one dose), group 3 (n = 8) 6 Gy total lymphoid irradiation (one dose), and group 4 (n = 9) chemotherapy alone. At the first evaluation, 13/36 patients in groups 1 and 2 had low growth hormone (GH) peaks after stimulation. The mean plasma IGF I concentrations (z score) were similar in groups 1 (-2.9 +/- 0.3) and 2 (-2.5 +/- 0.3), and in groups 3 (-1.4 +/- 0.3) and 4 (-1.4 +/- 0.7), but those of group 1 were lower than those of groups 3 (P < 0.01) and 4 (P < 0.05), and those of group 2 than those of group 3 (P < 0.05). BMI during the 5 years after BMT did not change in groups 1 and 2, decreased in group 3, and increased in group 4. However, these changes were not significant. Most of the patients given TBI had BMI below the mean at 2 (66%) and 5 (57%) years later. Their BMI and leptin concentrations correlated positively with each other (P = 0.005), and negatively with GH peak (P = 0.02 for BMI and 0.007 for leptin). In conclusion, this study suggests that TBI actually decreases GH secretion and is followed by a persistent low BMI. The negative relationship between GH peak and leptin may indicate that both are markers of a TBI-induced hypothalamic-pituitary lesion.

Adolescent↗
PubMed2000

[Hand-held ultrasound-guided vacuum biopsy of mammary lesions--first experiences].

OBJECTIVE: Evaluation of indications for ultrasound guided hand-held Mammotome-biopsy. MATERIAL AND METHODS: To achieve breast diagnosis 50 ultrasound guided hand-held Mammotome-biopsies were performed between January 3rd and April 4th, 2000. RESULTS: 34 patients presented with non-palpable, 16 with palpable breast lesions. The benign-to-malignant ratio was 80% to 20%. Complete removal of the lesion we established in 22 (44%) of all 50 procedures. Definitive breast diagnosis of malignancies was achieved in all but one case. CONCLUSIONS: We regard the ultrasound guided hand-held Mammotome-biopsy as diagnostic and surgical instrument that provides the clinician with a flexible and easy to use method of accurate breast diagnosis. Lesions too small, superficial, or deep for conventional core biopsy are indications for a ultrasound guided Mammotome-biopsy as well as abnormalities where wide sampling is considered important or small fibroadenomas. However, standard of care for breast diagnosis remains the conventional hand-held 14-gauge-core-biopsy. For malignant lesions hand held mammotomy must be regarded as a diagnostic and not a therapeutic procedure.

Biopsy, Needle↗
PubMed2000

Boxing and running lead to a rise in serum levels of S-100B protein.

Permanent neurological dysfunction is the primary medical concern of boxing. Recently it was reported that patients presenting elevated levels of the glial protein S-100B in serum after minor head injuries are more prone to develop neuropsychological deficits than patients with lower levels of S-100B protein. We assessed this protein before and after amateur boxing competitions (n = 10) and sparring bouts (n = 15). In several control groups, we investigated S-100B levels of participants before and after a 25 km race (n = 11), jogging (10 km, n = 12), short-term running (n = 12), and heading footballs (n = 12). There was an increase in S-100B protein after boxing and the running disciplines but not after ergometer cycling or soft heading of footballs. The increase in S-100B protein concentrations due to competitive boxing and after the 25 km race was significantly higher than that after performing other disciplines (p < 0.001). There was no significant difference between the increases caused by sparring and the running disciplines (p = 0.21). The number and severity of the strikes to the head correlated significantly with the increase in the S-100B protein levels. Levels of S-100B protein known to be associated with neuropsychological deficits were not reached in our study. In professional boxing, much higher levels are to be expected and would be worthy of investigation.

Adolescent↗
PubMed2000

Gene therapy of lymphoid primary immunodeficiencies.

Gene therapy offers an attractive option to the most severe forms of primary immunodeficiency diseases. Identification of disease-associated genes as well as advances in the technology of gene transfer into hematopoietic progenitor cells have set the basis for the first clinical trials. Settings characterized by the potential for a selective advantage provided to transduced cells are the first diseases to target. The recent example of successful treatment of severe combined immunodeficiency-X1 (gammac deficiency) illustrates this potential.

Genetic Therapy↗
PubMed2000

Gastric adenocarcinoma in a patient with X-linked agammaglobulinaemia.

Patients with primary immunodeficiencies are at high risk for developing haematological malignancies and, to a lesser degree, carcinoma. We report a patient with ascertained X-linked agammaglobulinaemia who developed a gastric carcinoma involving the distal part of the stomach associated with chronic atrophic gastritis and intestinal metaplasia. These latter conditions are considered to be precursor conditions and the role of chronic infections is likely. Patients with X-linked agammaglobulinaemia, as with other primary immunodeficiencies, could benefit from regular gastrointestinal evaluation, leading to early diagnosis and treatment of carcinoma.

Adenocarcinoma↗