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Biomedical subjects

M Lechleitner

Publications and source records attributed to M Lechleitner.

At least 55 records · Page 3Linked to original sources
PubMed1994

The immunosuppressive substance 2-chloro-2-deoxyadenosine modulates lipoprotein metabolism in a murine macrophage cell line (P388 cells).

A recently developed immunosuppressive substance, 2-chloro-2-deoxyadenosine (2-CdA), was reported to inhibit monocyte functions at low concentration. Because macrophages play a key role in the formation of atherosclerotic plaques, it was of interest to study the effect of 2-CdA on cellular lipid metabolism. For this purpose we have used a macrophage cell line (P388) to perform incubation studies in the presence of acetylated low density lipoprotein (Ac-LDL) and 2-CdA. The addition of 2-CdA, in concentrations ranging from 5-20 nM, induced a dose-dependent decrease in cellular cholesterol content and in the amount of extracellular [14C]oleic acid (OA) incorporated into the cholesteryl ester (CE) fraction. The effect was maximized at 20 nM 2-CdA with an 86% reduction in cholesterol esterification compared to controls (P < 0.008). To evaluate the mechanism of interaction of 2-CdA with cellular lipid metabolism, deoxycytidine (dCyt) and 3-methoxybenzamide (3-MOB), substances known to antagonize the effect of 2-CdA in different ways, were co-administered with 2-CdA. dCyt, a competitive inhibitor of dCyt kinase, which catalyzes phosphorylation to the active metabolite, antagonized the effects of 20 nM 2-CdA, producing significantly greater incorporation of extracellular [14C]OA into the CE fraction than in the presence of 2-CdA alone (P < 0.0086). Co-incubation with 2-CdA and the poly-ADP-ribose synthetase inhibitor 3-MOB, which is known to render cells resistant to 2-CdA toxicity by preventing cellular nicotinamide adenine dinucleotide (NAD)- and adenosine triphosphase-depletion, also reversed the effect of 2-CdA on lipid accumulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylation↗
PubMed1994

Kinetics of lipids, apolipoproteins, and cholesteryl ester transfer protein in plasma after a bicycle marathon.

The short-term effects of prolonged intense exercise on plasma lipid transport parameters including cholesterol, triglycerides (TGs), low-density lipoprotein (LD) cholesterol, high-density lipoprotein (HDL) cholesterol, and its subfractions HDL2 cholesterol and HDL3 cholesterol, on apolipoproteins (apos) A-I, A-II, and B, and on mass and activity of cholesteryl ester transfer protein (CETP) were studied in eight male endurance-trained athletes over the first week after a bicycle marathon. CETP mass concentration in plasma was quantified by a newly developed immunoradiometric assay (IRMA). Plasma concentrations of cholesterol, TGs, LDL cholesterol, apo B, CETP, and cholesteryl ester transfer activity (CETA) were significantly reduced in the recovery period compared with pre-exercise values (cholesterol by 20%, P < .05; TGs by 63%, P < .05; LDL cholesterol by 32%, P < .05; apo B by 18%, P < .05; CETP mass by 29%, P < .05; and CETA by 14%, P < .05). HDL cholesterol and HDL2 cholesterol, in contrast, were significantly increased in the post-exercise period (HDL cholesterol by 12%, P < .05, and HDL2 cholesterol by 96%, P < .05), whereas HDL3 cholesterol showed a tendency to decrease in the late recovery period (by 8%, NS). Although changes in cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, apo B, and CETP mass and activity were already evident in the early recovery period, HDL2 cholesterol showed a delayed response, reaching its maximum 72 hours after initiation of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Low-density lipoproteins of the postprandial state induce cellular cholesteryl ester accumulation in macrophages.

Chemically or biologically modified low-density lipoproteins (LDL) but not native unmodified LDL lead to foam cell formation in monocyte-derived macrophages. Since the magnitude of postprandial lipemia after a challenge test seems to be associated with coronary artery disease, we tested the hypothesis that in the course of postprandial lipemia, LDL appear in plasma that are capable of leading to foam cell formation even without prior modification. We incubated the macrophage-like cell line P388 with unmodified postabsorptive and postprandial LDL from 17 healthy donors and measured the cellular cholesterol and triglyceride contents and amounts of exogenous [14C]oleic acid incorporated into the cholesteryl ester fraction. Postprandial LDL induced a significantly more pronounced cholesteryl ester accumulation than did postabsorptive LDL (477 +/- 286% versus 212 +/- 173%, respectively; P < .003). The increase in cellular total cholesterol was significantly higher as a result of cell incubation with postprandial LDL (107 +/- 61%) than with postabsorptive LDL (54 +/- 40%, P < .003), whereas no increase in triglyceride content was observed (P < .589) in either case. After CuSO4 incubation and incubation with P388 cells, postprandial LDL revealed more thiobarbituric acid-reacting substances than did postabsorptive LDL (55 +/- 10 versus 28 +/- 9 nmol/mg protein, P < .018; 28 +/- 4 versus 20 +/- 3 nmol/mg protein). The increase in cellular cholesteryl ester synthesis caused by postprandial LDL was reduced by more than 50% when lipoproteins and cells were incubated in the presence of ascorbic acid (P < .007).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Hypertriglyceridemia and acute pancreatitis].

Data of 26 patients suffering from severe pancreatitis, who were treated at the anesthesiologic intensive care unit during the years 1991 and 1992, were evaluated with respect to etiologic factors, especially hypertriglyceridemia, stage of the disease and clinical outcome. Hypertriglyceridemia was found in 13 cases (11 men, 2 women, mean age 42 +/- 9 years) with values between 330 mg/dl and 4000 mg/dl. Lipid electrophoresis revealed a pattern typical for type IV hyperlipidemia. Insulin dependent diabetes was present in 4 patients and 5 reported about an unusual high alcohol intake preceding pancreatitis. Beside surgical approaches, including drainage and lavage, and basic intensive care treatment plasmapheresis was performed in 8 patients with hypertriglyceridemia. 5 patients with pancreatitis and hypertriglyceridemia died out of multiorganic failure, and so the mortality rate was 38%. The group of patients with pancreatitis caused by cholelithiasis or chronic alcohol consumption showed a mortality rate of 46%. The poor outcome of pancreatitis associated with hypertriglyceridemia demonstrates the importance of the treatment of hypertriglyceridemia in order to prevent the development of pancreatitis. The determination of plasma triglyceride values should belong to the routine diagnostic procedures in acute pancreatitis.

Acute Disease↗
PubMed1992

[Snuff aspiration as a cause of recurrent pulmonary infiltrations in a 60-year-old patient with chronic renal failure].

Pulmonary infiltrations associated with renal failure demand several diagnostic procedures to exclude autoimmune disorders affecting both organ systems or to find an infectious cause of the disease. We report the case of a 60 year-old man with chronic renal failure and recurring pulmonary infiltrations. On admission to hospital all diagnostic parameters for systemic vasculitis, infectious or neoplastic disease were negative, including the histological report on transbronchial biopsies. Eventually, follow-up biopsies taken 3 months later showed vegetable fibres and necrosis due to intensive snuff abuse during the previous months. After the patient stopped taking snuff the pulmonary infiltrations improved quickly. Uraemic neuropathy, which may have facilitated aspiration, as well as the reduced pulmonary and systemic defence mechanisms due to chronic renal failure probably contributed to a considerable degree to the development of pulmonary infiltration.

Biopsy↗
PubMed1992

[Pravastatin, a new cholesterol synthesis inhibitor for lowering increased serum cholesterol].

The association between increased risk for coronary artery disease (CAD) and elevated plasma cholesterol has been firmly established. The beneficial effect of cholesterol lowering treatment modalities was confirmed in both primary and secondary intervention trials. Because long-term treatment is usually required for lipid lowering therapies the drugs used for lipid reduction have to be not only efficacious but also safe. Inhibitors of cholesterol synthesis that have become clinically available during the last few years, can reduce plasma levels of total cholesterol and low density lipoprotein (LDL)-cholesterol very effectively. In the Familial Atherosclerosis Treatment Study (FATS) an intensive cholesterol lowering treatment modality consisting of a combination of an inhibitor of cholesterol synthesis and colestipol reduced the progression of coronary lesions and caused a partial regression of such lesions. Among the various inhibitors of cholesterol synthesis developed recently, pravastatin appears to be tissue-specific because of its hydrophilic property.

Cholesterol↗
PubMed1991

Long-term effect of intensified insulin treatment on lipid parameters in diabetes mellitus type I.

Premature atherosclerosis is often found in patients with diabetes mellitus (DM) type I, and alterations in lipid metabolism seem to play an important role in the development of this complication. Intensified insulin therapy improves glycemic control parameters significantly. To evaluate the effect of this optimized insulin treatment (OIT) not only on glycemic control, but also on plasma lipids, 24 patients with DM type I (19 men and 5 women, 18 to 61 years) were switched from a standard insulin therapy to a regimen of OIT which has been maintained for more than 3 years now. After 2 years on OIT a reduction of HbA1c values from 8.1% to 7.5% (p less than 0.01) was accompanied by an increase in HDL cholesterol from 52 to 67 mg/dl (p less than 0.05) and a decrease of triglyceride levels from 319 to 67 mg/dl (p less than 0.001). At the end of the second year on OIT some of the patients exhibited a reversal of the favorable trend in HbA1c and lipid values. Intensified instructions regarding the implementation of OIT were therefore repeated and resulted in a renewed improvement of overall HbA1c, HDL cholesterol and triglyceride levels to 6.43%, 67 mg/dl, and 78 mg/dl, respectively. Our findings underline the value of OIT not only for glycemic control, but also for the control of plasma lipids considered to be major risk factors for coronary artery disease.

Adolescent↗
PubMed1991

[An idiopathic floating left-ventricular thrombus].

Four weeks after appendicectomy a 28-year-old man developed dragging pains in the left calf. Left popliteal, posterior tibial and dorsalis pedis arteries could not be palpated. Angiography revealed an embolic occlusion of the left superior femoral artery at the level of the adductor canal. Echocardiography demonstrated a pedunculated left ventricular thrombus, 3.5 x 2.0 cm, as a possible source of the embolus. After successful trifurcation embolectomy and saphenous vein patch-plasty acenocoumarol, 4 mg/d and heparin, 3 x 7500 IU/d were administered. Because the thrombus failed to shrink, systemic thrombolysis, initially 750,000 IU streptokinase and 3000 IU heparin i.v., was begun. After five days the thrombus diameter had decreased to 0.7 cm. But because thrombus movement had increased, streptokinase was replaced by 70 IU/d ancrod i.v. The thrombus completely disappeared within two weeks. The patient was symptom-free during the period of anticoagulation with acenocoumarol. Six months later echocardiography confirmed the absence of thrombus in the left ventricle.

Acenocoumarol↗
PubMed1991

[Cerebrovascular disorders as a manifestation of a generalized disease].

During the last years several risk factors for cerebrovascular disease (CVI) could be identified by epidemiologic studies; the incidence of CVI, like that of coronary artery disease, seems to be closely related to high blood pressure, hyperlipidaemia, smoking and diabetes mellitus. The diagnostic difficulties in CVI, especially concerning the localization and size of vascular lesions, explain controversal results in the evaluation of different clinical studies. A comparison of these results is often hard to perform also out of the different statistical methods applied in the various trials. The development of improved diagnostic methods, especially ultrasonography, which allow a better definition of disease processes, offers an advantage for controlled screening and intervention trials. After all further improvements in disease prevention as well as in diagnostic and therapeutic procedures require an intensive co-operation between internal medicine and neurology.

Cardiovascular Diseases↗
PubMed1991

[Risk factors for coronary heart disease].

Cardiovascular disease remains the major cause of death in the industrialized world with dyslipidemia, hypertension and cigarette smoking leading a long list of risk factors. Recently, controversy arose from some critical articles expressing concern about the evaluation and interpretation of statistical data of epidemiologic studies. One study using covariance analysis reported an absence of the widely accepted negative association between coronary heart disease (CHD) and high density lipoprotein (HDL) cholesterol. Also criticism was expressed regarding the cost-effectiveness of preventive measures such as the use of lipid lowering drugs on life expectancy. Because of such recent scientific controversy and discussions already taking place in the media, we have summarized in this article recent epidemiologic evidence including a meta-analysis of the major epidemiologic studies on HDL. We have directed particular attention to 3 large epidemiological studies, i.e., the Familial Atherosclerosis Treatment Study (FATS), the Program on the Surgical Control of the Hyperlipidemias (POSCH), and the Cholesterol Lowering Atherosclerosis Study (CLAS), all of which have clearly demonstrated a desirable effect of intensive lipid lowering therapy on coronary lesions.

Austria↗
PubMed1989

Immunohistological assessment of bone marrow biopsies from patients with hairy cell leukemia: changes following treatment with alpha-2-interferon and deoxycoformycin.

Forty-six bone marrow biopsies from twelve hairy cell leukemia (HCL) patients, treated with either interferon(IFN)-alpha-2 (n = 8) or 2'deoxycoformycin(DCF) (n = 4), were examined using cryostat sections and an immunoperoxidase technique. Using this sensitive method we were able to demonstrate residual hairy cell (HC) infiltration in five cases, in which evaluation with conventional staining techniques on plastic embedded biopsies revealed complete remission. The amount of HCs in these five samples ranged from 1 to 7% (mean: 3%) of bone marrow cells. Consecutive biopsies in individual HCL patients revealed no changes of the immunological phenotype (CD19, CD22, CD25, CD10, CD11c, FMC7, HLA-DR, surface immunoglobulins) during IFN and DCF treatment. Within the infiltrated bone marrow a considerable number of "reactive" T lymphocytes was identified with prevalence of the T-helper (CD4+) subtype in untreated cases, whereas T-suppressor/cytotoxic (CD8+) cells were within the normal range. IFN treatment resulted in a reduction of CD4+ T lymphocytes (p less than 0.02). Minor alterations of CD8+ T lymphocytes and NK cells (HNK-1 + lymphoid cells) were found in bone marrow during IFN treatment. In DCF-treated patients bone marrow T lymphocytes were markedly reduced below the values of normal bone marrow. This DCF-induced T-cell depression might be related to the clinical observation of persistent cellular immune dysfunctions in HCL patients despite a DCF-induced remission.

Adult↗
PubMed1989

Combination effects of human recombinant interferon (alpha-2-arg, gamma) and cytotoxic agents on colony formation of human melanoma and hypernephroma cell lines.

Malignant melanoma and hypernephroma show marginal response to chemotherapeutics and interferons when used as single agents. Using a modified soft agar clonogenic assay we investigated the antiproliferative effects of combinations of vinblastine, bleomycin, adriamycin, interferon alpha and gamma. On the hypernephroma cell line combinations of bleomycin and adriamycin with interferon gamma as well as combinations of both interferon types resulted in a synergistic antiproliferative effect. On the melanoma cell line combinations of bleomycin and adriamycin with interferon alpha and combinations of vinblastine with interferon gamma acted in a synergistic manner. All other combinations tested were only additive. Thus far, we could not find any antagonistic effect of interferons and chemotherapeutics.

Antineoplastic Agents↗
PubMed1987

Diagnostic and prognostic value of immunohistological bone marrow examination: results in 212 patients with lymphoproliferative disorders.

Cryostat sections of 246 consecutive bone marrow biopsies from 212 patients with lymphoproliferative disease were investigated using a panel of monoclonal antibodies (MOAb's) and an immunoperoxidase technique. Bone marrow involvement was demonstrated by immunohistological examination in 121/160 patients (76%) with non-Hodgkin lymphomas (NHL) and 16/23 patients (70%) with plasma cell malignancies; the definite immunological diagnosis could be performed in 77% and 88%, respectively. Reactivity with the MoAb Ki-67 correlated with clinical parameters: in all cases exhibiting more than 5% positive cells an unfavourable course was seen, independent of the histological subtype. Another MoAb of potential prognostic relevance is KiM 4 b, which reacts with follicular dendritic cells (FDC). Besides the presence of FDC in germinal center tumors (CB/CC and CC-NHL) we found FDC in a minority of cases with B-CLL (5/44) and IC lymphoma (4/18). In the latter group 3/4 patients showed a favourable clinical course (vs 2/14 without FDC). The MoAb Tü 1 could discriminate between the lymphoplasmocytoid (11/12 positive) and the lymphoplasmocytic (0/6 positive) subtype of IC lymphoma and has proven of diagnostic importance. Expression of IL-2 receptors, detected by MoAb anti-Tac (CD 25), was demonstrated on leukemic cells from patients with hairy cell leukemia (100%), B-CLL (82%), IC (61%), CC (50%) and CB/CC lymphoma (50%). A considerable number of reactive T-lymphocytes (5%-60% of tissue cells) were identified among the neoplastic B cells with a predominance of CD4+ cells in most cases with NHL, whereas the CD4+/CD8+ ratio was significantly lower in myelomas and non-infiltrated bone marrows. The potential meaning of these findings is discussed. The immunohistological bone marrow analysis represents an important additional method in the diagnostic procedures of lymphoproliferative diseases involving the bone.

Antibodies, Monoclonal↗