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Biomedical subjects

M Dietrich

Publications and source records attributed to M Dietrich.

At least 55 records · Page 3Linked to original sources
PubMed1997

Evidence for a conserved binding motif of the dinuclear metal site in mammalian and plant purple acid phosphatases: 1H NMR studies of the di-iron derivative of the Fe(III)Zn(II) enzyme from kidney bean.

The di-iron core of mammalian purple acid phosphatases has been reproduced in the plant enzyme from kidney bean (Mr 111000) upon insertion of an Fe(II) ion in place of the native zinc(II) in the dinuclear Fe(III)Zn(II) core. The shortening of the electronic relaxation time of the metal centre allows detection of hyperfine-shifted 1H NMR resonances, although severe broadening due to Curie relaxation prevents independent signal assignment. Nevertheless, comparison of the spectral features of the structurally characterized plant enzyme with those of the mammalian species, which were previously extensively assigned, is consistent with a close similarity of the metal-binding sites, also suggested by previous sequence-alignment studies. Some differences appear to be mainly localized at the M(II) site. Spectral comparison was also carried out on the Fe(III)Co(II) derivatives.

Acid Phosphatase↗
PubMed1997

Reactivity of a population of armadillo lymphocytes with an antibody to human gamma,delta T-cells.

Reactivity of lymphocytes from the nine-banded armadillo (Dasypus novemcinctus) was examined by flow cytometry using a panel of 16 commercially available fluorochrome-conjugated monoclonal antibodies raised against human or murine leukocyte antigens. The only reactivity observed was with antibody TCRdelta1, directed against a common determinant on the delta chain of the human gamma,delta T-cell receptor. Using this antibody, a distinct, bright population of lymphocytes was seen in the peripheral blood in all of 47 animals examined, accounting for 2.0-47.1% of lymphocytes (median, 10.6%). The gamma,delta-reactive lymphocyte population comprised a greater percentage of intraepithelial lymphocytes in the small intestine than in the blood; variable percentages of gamma,delta-reactive cells were also observed in the spleen, thymus, lymph nodes, and bone marrow, and in cutaneous lepromas. In armadillos with disseminated Mycobacterium leprae infection, a significantly greater percentage of circulating lymphocytes reacted with the anti-gamma,delta antibody. This is the first described reactivity of armadillo lymphocytes with a monoclonal antibody to a lymphocyte antigen, and it may offer a useful tool in disease models involving the armadillo.

Animals↗
PubMed1997

Patterns of mycobacterium avium culture and PCR positivity in immunodeficient HIV-infected patients: progression from localized to systematic disease, German Aids Study Group (GASG/IDKF).

Our aim was to establish the frequency and the longitudinal pattern of MAC culture positivity in late stage HIV-infected patients. Two other aims were to analyse risk factors for progression from localized to systemic disease and the value of PCR diagnosis using blood specimens. A total of 107 patients were recruited to be followed for 32 weeks. Prior MAC treatment and CD4 > 100/microliters were exclusion criteria. A total of 56 patients showed M. avium in at least 1 culture. 10/37 patients with MAC detected by culture first in 'non-sterile' specimens (stool, sputum) and urine progressed to systemic disease as determined by positive blood culture. Risk factors associated with this progression were a high symptom score at baseline, lymphadenopathy, anaemia, and low platelets. PCR was less sensitive than culture in detection of M. avium in blood specimens: Only 7/29 patients with positive blood cultures had a positive PCR at the same time. We conclude that symptomatic patients with advanced HIV-infection have a high frequency of MAC detection. Progression from localized to systemic culture positivity is associated with risk factors. Early 'pre-emptive' therapy is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Supportive pentoxifylline in falciparum malaria: no effect on tumor necrosis factor alpha levels or clinical outcome: a prospective, randomized, placebo-controlled study.

Pentoxifylline (POF) may suppress overproduction of tumor necrosis factor alpha (TNF alpha), which is thought to contribute to complications of human falciparum malaria. However, POF is believed to improve impaired capillary blood flow, which can be impaired in falciparum malaria. To test whether POF affects TNF alpha serum levels or other variables in this disease, we administered POF (20 mg/kg/day intravenously in 150 ml of saline for five days) randomized versus placebo (150 ml of saline without POF) in addition to standard antimalarial therapy. After recruitment of 51 patients with Plasmodium falciparum malaria, those receiving POF had more nausea and abdominal discomfort than the placebo group, as expected. Eleven of 27 patients receiving POF and three of 24 patients receiving placebo requested termination of the study medication (P < 0.05). Pentoxifylline did not change the decrease of TNF alpha levels or affect the clinical course in a significant way. Since POF failed to improve the clinical situation or to impact numerous laboratory parameters (including TNF alpha, thrombin-antithrombin III, thrombomodulin, and human neutrophil elastase), the study was terminated earlier than planned. While this study does not specifically address cerebral complications of malaria, the results suggest that POF is not useful as a routine adjunct to the standard therapy of falciparum malaria.

Acetaminophen↗
PubMed1997

Blood coagulation and thrombosis in patients with ovarian malignancy.

Ovarian cancer cells appear to be capable of both thrombin formation and induction of fibrin degradation which may be essential prerequisites for the development of deep vein thrombosis (DVT) as well as the spread of malignancy. To study further this coagulation-cancer interaction in 60 patients with untreated ovarian cancer of FIGO stage I-IV the incidence of DVT was recorded pre-operatively, post-operatively on day 1, 3, 5, 7, 10, before each of six cycles of Cisplatinum/ Epirubicin/Cyclophosphamide chemotherapy, during follow-up and in the post-operative period of second look surgery. In addition, blood coagulation tests results were determined prospectively. Two patients were excluded from these calculations due to previous DVT 5 to 6 weeks before the diagnosis of ovarian cancer but all patients were eligible for surgery and randomized to receive either daily low molecular weight heparin (LMWH) (n = 28) or unfractionated heparin (UFH) (n = 32) for perioperative thrombosis prophylaxis until the 7th post-operative day. According to the FIGO stage, patients were equally distributed in the 2 heparin treatment groups. The predictive value of pre-operative coagulation test results, clinical parameters, and type of heparin used were tested in univariate and multivariate analysis for development of post-operative DVT and overall patients survival. Impedance plethysmography for DVT screening was used. The presence of DVT was then confirmed by phlebography. Only D-dimer and fibrinogen levels were correlated significantly with the FIGO stage while antithrombin, protein C, and plasminogen activator inhibitor activity were not. The incidence of DVT was 6.7% (4/60) up to the 7th and 8.3% (5/60) between the 8th and 29th post-operative day. DVT occurred in 10.6% (5/47) during chemotherapy. Pre-operative coagulation test results, the type of heparin used, and clinical parameters were not significant risk factors for post-operative DVT development in univariate analysis. The D-dimer and fibrinogen levels were significant risk factors for reduced overall survival in univariate analysis but only the FIGO stage was an independent predictor (in multivariate analysis). After a median follow up of 26.5 months (min. 8 months, max. 41 months), 21.4% of LMWH treated and 37.5% of UFH-treated patients died of cancer (p = 0.26). Pre-operative test results were neither predictive for DVT nor the outcome of cancer but patients showed an improved though not statistically significant overall survival after LMWH treatment.

Aged↗
PubMed1997

Smoking cessation in military personnel.

Tobacco use is the single most important preventable cause of death in military personnel. The purpose of this randomized clinical trial was to evaluate the effectiveness of two behavioral interventions when added to nicotine-replacement therapy on smoking cessation. The sample of 512 included 52% active duty military, 29% family, 11% retirees, and 8% Department of Defense civilians. There was a main effect of compliance at the end of the program (EOP); 69% of those who attended 75% of the classes were abstinent from tobacco; regression analysis found the more intensive program to be twice as effective at EOP and at 3 months, an outcome not continued at 6 months. The longer, more intensive Vanderbilt University Medical Center program was significantly more effective at helping the civilian portion of the population (85% versus 60% in the American Cancer Society program) but not the active duty participants.

Adult↗
PubMed1997

Clinical course of human immunodeficiency virus type 1 associated pulmonary tuberculosis during short-course antituberculosis therapy.

To describe the clinical response to antituberculosis therapy in HIV-1 disease, 49 HIV-1 positive Ugandan adults (mean age 29.4 years; 68% men) with active pulmonary tuberculosis (PTB) were studied in a trial of rifampicin containing short-course antituberculosisis regimens. At presentation, 18 patients were PPD non-reactors (PPD skin test induration < 2mm), ten patients (20%) had non-cavitary lung disease. The mean CD4 lymphocyte count at presentation was 339/microliters (+/- SD 275). Among patients with abnormal baseline clinical values, the median time to resolution of fever, weight gain of 10%, increase of haemoglobin to 10g/dl and of Karnofsky performance score (KPS) to 80 occurred before sputum smear and culture conversion. Short-term survival was associated with: baseline lymphocytes < 1200/microliters, (Odds ratio (OR) 17.5), CD4+ lymphocytes < 200/microliters (OR 9.8), cavitary lung disease, (OR 0.6), atypical chest radiograph, (OR 6.7), and PPD non-reactivity, (OR 13.5), PPD non-reactivity and non-cavitary disease were associated with significantly lower CD4 lymphocyte counts. Affordable serial measurements parallel the response to therapy and predict survival in HIV-associated PTB.

AIDS-Related Opportunistic Infections↗
PubMed1996

Autoantibody reactivity in serum of patients with Alzheimer's disease and other age-related dementias.

Serum antibodies against a series of antigens, including an organ-specific central nervous system (CNS) antigen and the neurotransmitter serotonin, were investigated in 22 patients with Alzheimer's Disease (n=15) and other age-related dementias (n=7) by indirect immunofluorescence assay and enzyme-linked immunosorbent assay. Patients with dementia showed an increase of antibody-positive sera against nuclear antigen, gastric parietal cells, CNS antigen, gangliosides (Gm1), laminin, and keratin. Alzheimer's Disease patients alone exhibited antibodies against CNS antigen. However, the results do not show sufficient specificity and sensitivity for use as a diagnostic indicator.

Aged↗
PubMed1996

A human SP-C promoter fragment targets alpha 1-proteinase inhibitor gene expression to lung alveolar type II cells in transgenic mice.

A 1.277 kb promoter fragment of the gene encoding one of the lung surfactant proteins, SP-C, was cloned from a human genomic library and characterized using the human alpha 1-proteinase inhibitor (alpha 1PI) gene as reporter. Messenger RNA for human alpha 1PI isolated from a single transgenic mouse line was detected solely in lung tissue. Using immunogold electron microscopy, accumulation of human alpha 1PI was shown unambiguously to occur only in type II pulmonary cells and, in discrete amounts, in the alveolar lining fluid. The protein was secreted and glycosylated showing a molecular weight close to that of plasma-derived human alpha 1PI.

Animals↗
PubMed1996

Sera from patients with falciparum malaria induce substance P gene expression in cultured human brain microvascular endothelial cells.

Substance P is a pluripotent neuropeptide capable of inducing neurogenic inflammation, immunoregulation, and vasodilatation. In an effort to contribute to the understanding of the pathophysiology of cerebral malaria, we have evaluated the effects of sera obtained from patients suffering from severe or mild malaria and from a healthy donor with no previous history of exposure to malaria on the expression of the substance P gene by cultured human brain microvascular endothelial cells (HBMEC) and human umbilical-vein endothelial cells. PCR, Southern blotting, hybridization with an internal probe, and densitometry demonstrated that treatment of HBMEC with sera from patients with severe malaria caused remarkably increased expression of the substance P gene. In HBMEC, substance P was not significantly influenced by serum from a healthy donor. Substance P was expressed at almost undetectable levels in untreated HBMEC. Treatment of cultured human umbilical-vein endothelial cells with the same sera produced no signal. The influence of different sera on the expression of substance P by HBMEC suggests that substance P expression may be involved in events leading to the development of severe malaria.

Blood Proteins↗
PubMed1996

Blood coagulation during adjuvant epirubicin/cyclophosphamide chemotherapy in patients with primary operable breast cancer.

PURPOSE: Influences of adjuvant epirubicin/cyclophosphamide (EC) chemotherapy on blood coagulation were investigated in patients with operable breast cancer and the incidence of thromboembolic events was recorded. PATIENTS AND METHODS: In 50 consecutive node-positive breast cancer patients, serial coagulation studies (fibrinogen method of Clauss, antithrombin III, protein C amidolytic methods, D dimer enzyme-linked immunoadsorbent assay [ELISA] techniques, and plasminogen activator inhibitor [PAI] activity u-PA inhibition test) and impedance plethysmography (IPG) for screening of deep vein thrombosis (DVT) were performed preoperatively and postoperatively, before each of six cycles of adjuvant chemotherapy (60 mg/m2 epirubicin and 600 mg/m2 cyclophosphamide) and 3 months thereafter. Seventy-two healthy women served as controls. RESULTS: During chemotherapy, the phlebographically proven DVT incidence was 10% (n = 2 after second cycle; n = 3 after third cycle). Preoperative levels of D-dimer, fibrinogen, and the PAI activity were significantly higher than in healthy women and only mean levels of the D-dimer were significantly higher in patients with DVT compared with patients without DVT. Postoperatively, only D-dimer and fibrinogen levels significantly increased, while in the course of chemotherapy, these levels were significantly decreased. Mean D-dimer levels and PAI increased steadily in patients with DVT. Preoperatively and during chemotherapy, levels of antithrombin III and protein C were within the normal range. Only one patient with DVT had decreased protein C levels throughout chemotherapy. CONCLUSION: Monitoring with sophisticated coagulation tests during adjuvant EC chemotherapy for breast cancer does not identify patients at higher risk for DVT development. Preoperatively, in patients with later DVT, an imbalance of hemostasis is already present; thus, thrombosis might predominantly be initiated by malignancy-induced hypercoagulability and secondarily by the influence of EC chemotherapy. Prospective randomized trials must determine whether prophylactic anticoagulation during EC chemotherapy reduces the incidence of DVT.

Adult↗
PubMed1996

Architectural features and perceptions of community residences for people with mental retardation.

Architects, group home administrators, people with mental retardation, family members of people with mental retardation, and college undergraduates substantially agreed regarding the rated homelikeness of slides of interiors of 20 community residences for people with mental retardation ranging from institutional to homey, mean r = .87. Clusters of physical features identified using an architectural inventory were found to be associated with homelikeness ratings. Adjectives applied to rooms with these features were determined using a Q-sort method. Two factors were identified from Q-sort correlations: Homelikeness-Institutionality and Spatial Organization as well as a third variable, privacy.

Adolescent↗
PubMed1996

Interdependence of architectural features and program variables in community residences for people with mental retardation.

In an earlier study, we found that architects, group home administrators, people with mental retardation, family members of people with mental retardation, and college undergraduates rated the homelikeness of slides of community residences for people with mental retardation similarly. In addition, clusters of physical features were identified that were specifically associated with homelikeness ratings. In the present study, behavior of residents with mental retardation living in those residences was assessed using the Aberrant Behavior Checklist and direct behavioral observations. After statistically controlling for confounding variables, we found that adaptive and maladaptive behavior covaried with homelikeness ratings. In addition, we were able to identify associations between specific architectural features of residential settings and the behavior of residents living in those settings.

Activities of Daily Living↗
PubMed1995

In vivo cloning by homologous recombination in yeast using a two-plasmid-based system.

In order to reduce the number of classical DNA manipulation and ligation steps in the generation of yeast expression plasmids, a series of vectors is described which facilitate the assembly of such plasmids by the more efficient 'recombination in vivo' technique. Two sets of vectors were developed. The first set, called 'expression vectors', contains an expression cassette with a yeast promoter and the PGK terminator separated by a polylinker, and an Escherichia coli replicon. Subcloning in these vectors of a DNA fragment generates a 'transfer vector' which is compatible with the second set of E. coli-yeast shuttle vectors. This set of 'recombination vectors' contains a cassette for a functional copy of a gene complementing a host strain auxotrophy or a bacterial gene conferring an antibiotic resistance to the plasmid-bearing host. Plasmid copy numbers can be modulated through the use of URA3 or URA3-d as the selective marker together with an ARS/CEN and the 2 microns replicon. Integration of the cloned DNAs into the yeast linearized replicative vectors occurs by recombination between homologous flanking sequences during transformation in yeast or E. coli. All the vectors contain the origin of replication of phage f1 and allow the generation of single-stranded DNA in E. coli for sequencing or site-directed mutagenesis.

Amino Acid Sequence↗
PubMed1995

Investigations on autologous T-cells for adoptive immunotherapy of AIDS.

We report on the preclinical results of an immunotherapeutic approach of AIDS mediated by ex vivo propagated CD4+ and CD8+ T-cells. A mean yield of 6.23 x 10(9) lymphocytes, containing 1.82 x 10(9) CD4+, 3.23 x 10(9) CD8+ T-lymphocytes and 8.39 x 10(6) CD34+ peripheral blood progenitor cells (PBPC) were be obtained by continuous flow cytapheresis (CFC) in 15 asymptomatic HIV infected patients (CD4-count > 350/mm3). The CD4/CD8 ratio (mean: 0.53, SD: +/- 0.15) in the cell concentrates reflected the distribution of the circulating lymphocyte subsets in vivo. Absolute lymphocyte counts decreased at a mean of 404/microliter (25%) immediately after CFC but were replaced from the extravascular pool within one hour. Neither the CD4/CD8 ratio nor p24-antigen and neopterin levels did change significantly after cell separation. No alteration of the number of proviral DNA copies (1/10(3)-1/10(6)) could be detected in peripheral T-helper cells by semiquantitative PCR after lymphapheresis. Cells were cryopreserved in liquid nitrogen without substantial loss of viability or function. Ex vivo propagation of T-cells in a strictly autologous manner in the presence of PHA + IL-2 for 14d resulted in a 50-fold expansion rate (140-fold in healthy controls, p < 0.001). Viral replication could be controlled but not completely eliminated by cocultivation with autologous CD8+ T-lymphocytes as measured by limiting dilution nested PCR (NPCR). The expanded cells showed the typical phenotype of highly activated memory type T-lymphocytes (CD3+ CD45RO+ CD25+ HLA-DR+). The distribution of CD4+ and CD8+ T-cells did not reveal significant changes before and after culture indicating that both subsets were equally expanded. Functionally important membrane or intracellular epitopes which were found to be decreased in HIV infected subjects (CD7, CD55, CD59) before culture were reconstituted after ex vivo propagation of T-cells. The functional importance of the up-regulation of complement regulating epitopes (CD55, CD59) after culture could be proven by a significant inhibition of cytolysis of T-cells in the presence of autologous complement. The majority (75%) of expanded CD8+ T-cells stained positive with mAb TIA-1 which is directed to intracellular granules within cytotoxic T-cells. Furthermore, programmed cell death of expanded T-cells could be prevented by cocultivation with fibroblasts which are believed to secrete a cytokine pattern preventing activated T-cells from apoptosis after withdrawal of IL-2 and other stimuli.(ABSTRACT TRUNCATED AT 400 WORDS)

AIDS-Related Opportunistic Infections↗