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Biomedical subjects

T Mäki

Publications and source records attributed to T Mäki.

At least 19 recordsLinked to original sources
PubMed2006

Development of permanent national register of blood component use utilizing electronic hospital information systems.

BACKGROUND AND OBJECTIVES: We wanted to establish a permanent national database system, which can be utilized to study transfusion recipients and blood use in Finland. MATERIALS AND METHODS: A regularly updated register for permanent use was developed. To study the usability of the database, years 2002 and 2003 were further analysed. Database included all transfused patients in major blood-transfusing hospitals from four university and five central hospital districts managing altogether 63% of Finnish inpatient hospital episodes. RESULTS: Audit of gathered data reveal 96.8% match in adult blood components with Finnish Red Cross, Blood Service sales figures. Model data set includes 59,535 transfused patients (44.3% men and 55.7% women) having received 529,104 blood components. Half of all blood units were transfused in connection with surgical operations. Most of the blood recipients were elderly (51.6% are over 64 years of age). Blood-component use and transfusion-related costs varied widely between hospitals. CONCLUSION: Hospital data managing systems can be useful for creating a population-based database system to monitor and compare transfusion practices. This record provides information about transfusion epidemiology for transfusion professionals, hospital management, and hospital administration.

Adolescent↗
PubMed2005

Inhibition of c-kit tyrosine kinase by imatinib mesylate induces apoptosis in mast cells in rheumatoid synovia: a potential approach to the treatment of arthritis.

BACKGROUND: Mast cells have been implicated in the pathogenesis of arthritis, but elucidation of their precise role has been hampered by a lack of efficient and selective inhibitors of their function. OBJECTIVE: To elucidate the role of mast cells in the pathogenesis of rheumatoid arthritis (RA) and to assess whether apoptosis of cultured and synovial tissue mast cells can be induced by inhibiting mast cell growth factor receptor, c-kit tyrosine kinase. METHODS AND RESULTS: Double staining with tumour necrosis factor (TNF) alpha and tryptase antibodies showed the presence of TNFalpha positive mast cells in human rheumatoid synovial tissue. Selective activation of mast cells by anti-IgE resulted in production of TNFalpha in synovial tissue cultures. Inhibition of the c-kit tyrosine kinase with imatinib mesylate (1.0-10 micromol/l) induced profound apoptosis in cultured mast cells as judged by typical apoptotic morphology, increased number of apoptotic nucleosomes, and activation of caspases 8 and 9. Importantly, imatinib also induced apoptosis of mast cells in explant cultures of synovial tissue obtained from patients with RA as judged by a TUNEL assay. Inhibition of c-kit tyrosine kinase was accompanied by significant reduction of TNFalpha production in synovial tissue cultures. CONCLUSION: Mast cells may have a role in the pathogenesis of RA, and inhibition of c-kit may be a new means of inhibiting mast cell activity and of abrogating the contribution of mast cells to synovial inflammation in RA.

Animals↗
PubMed2002

Serum levels of amidated gastrin-17 and pepsinogen I in atrophic gastritis: an observational case-control study.

BACKGROUND: Helicobacter pylori infection is often diagnosed with non-endoscopic methods, such as serology or breath or antigen stool tests. These tests provide information on the presence or absence of the H. pylori gastritis only. We investigated whether atrophic gastritis can be diagnosed and typed non-endoscopically if the serum levels of pepsinogen I (S-PGI) and gastrin-17 (S-G-17) are assayed in connection with H. pylori testing. METHODS: The present investigation is an observational case-control study comprising 100 selected dyspeptic outpatients with (cases) or without (controls) advanced (moderate or severe) atrophic gastritis. Before the blood tests, all patients underwent a diagnostic gastroscopy with multiple biopsies. The series of cases includes 56 patients. Eight had an advanced antrum limited atrophic gastritis, 13 had resected antrum (in two of whom the corpus mucosa in the stump was atrophic), and 30 had corpus-limited atrophic gastritis. Four patients had an advanced atrophic gastritis in both the antrum and corpus (multifocal atrophic gastritis), and the whole stomach was removed in one patient. Twenty of the 44 controls had a non-atrophic H. pylori gastritis. Both the antrum and corpus were normal and healthy in 24 patients. The S-PGI and S-G-17 were determined with EIA methods using monoclonal antibodies to PGI and amidated G-17. Postprandial S-G-17 (S-G-17prand) was measured 20 min after a protein-rich drink. The H. pylori antibodies were assayed with a polyclonal EIA method. RESULTS: A low S-PGI (<25 microg/l; an empirical cut-off with best discrimination) was found in 31 of 37 patients (84%) with and in 3 of 63 patients (5%) without corpus atrophy in the biopsy specimens. A low S-G-17prand (<5 pmol/l) was found in all 8 patients with H. pylori-associated antral atrophy and in 11 of 14 patients (79%) with resected antrum but in 3 of 20 control patients (15%) with H. pylori-related non-atrophic gastritis. Median and mean values of both S-G-17prand and S-PGI decreased with increasing grade of antral and corpus atrophy, respectively. Among all patients with atrophic gastritis (multifocal atrophic gastritis, or atrophic gastritis limited to antrum or corpus) or resected stomach, 50 of 56 patients (89%; Cl 95%: 81%-97%) had a low S-PGI and/or a low S-G-17prand with positive H. pylori serology. Such low values werc found in 3 of the 44 control patients (7%; CI 95%: 0%-14%). CONCLUSIONS: Low serum levels of G-17prand and PGI are conceivable biomarkers of atrophic antral and corpus gastritis, respectively. A low S-G-17prand is a sign of the multifocal or antrum-limited atrophic gastritis in patients infected with H. pylori.

Antibodies, Bacterial↗
PubMed2001

Ethanol infusion increases ANP and p21 gene expression in isolated perfused rat heart.

Whether alcohol-induced heart failure is caused by a direct toxic effect of ethanol, metabolites, or whether it is a secondary result of neurohumoral, hormonal, or nutritional factors is not clear. To address this question a Langendorff retrograde coronary perfusion model of rat heart was used to study the effect of 0.5% (v/v) ethanol (n = 7) and 0.5 mM acetaldehyde (n = 9) on left ventricular expression of ANP, BNP, p53, p21, TNF-alpha,bax, bcl-2 as well as on DNA-fragmentation. Ethanol infusion of 150 min duration significantly induced both ANP and p21 mRNA expression of ventricular myocardium compared with hearts infused with vehicle (n = 8). Acetaldehyde did not exert any significant effects on any of the parameters studied, although the mean expression of TNF-alpha tended to be lower in the acetaldehyde-treated hearts than in control hearts. No evidence of increased DNA-fragmentation was found in ethanol or acetaldehyde treated groups. We conclude that ethanol per se is capable of inducing genes associated with hypertrophy and impaired function of the heart whereas a significant apoptosis is not involved in the initial phase of alcohol-induced cardiac injury.

Acetaldehyde↗
PubMed2000

Ethanol inhibits IgE-induced degranulation and cytokine production in cultured mouse and human mast cells.

Activated mast cells (MC) can produce a wide variety of potent inflammatory mediators. Excessive alcohol consumption is known to lead to immune deficiency and propensity for pneumonias in particular. As MCs are important in the first line of defence of mucosal membranes we have studied the effect of ethanol (EtOH) on several MC functions. EtOH attenuated dose dependently IgE-induced degranulation of mouse bone marrow derived mast cells (mBMMC) as reflected by the release of granule associated beta-hexosaminidase (beta-hex). A mean of 26 +/- 7% inhibition of beta-hex release was observed in the presence of 5/1000 (86 mM) EtOH and nearly complete inhibition in the presence of 20/1000 (344 mM) ethanol. The IgE-induced degranulation of mBMMC cultured with EtOH for seven days was inhibited to a similar degree as the degranulation of mBMMC exposed to EtOH for only one hour. Inclusion of 5/1000 (86 mM) ethanol in the medium reduced tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 production in human mast cell line (HMC-1) cells by 55 +/- 7% and 19 +/- 5%, respectively, and the presence of 20/1000 (344 mM) ethanol inhibited the expression 81 +/- 12% and 59 +/- 14% respectively. These results suggest that, in contrast to previous assumption, ethanol inhibits several critical MC functions at least in vitro. This inhibition of mediator, and cytokine release in particular, could contribute to the immune deficiency associated with chronic alcohol consumption.

Animals↗
PubMed1998

Effect of ethanol drinking, hangover, and exercise on adrenergic activity and heart rate variability in patients with a history of alcohol-induced atrial fibrillation.

To elucidate the mechanism of alcohol-induced atrial fibrillation (AF) we studied the heart rate variability and parameters of the adrenergic system during alcohol intake, hangover, and exercise in 6 men (mean age 43 years) prone to alcohol-induced AF, together with 6 age-matched controls. The ambulatory (15 hour) electrocardiogram was recorded and blood samples were taken for lymphocytic beta adrenoceptor, plasma catecholamine, and cyclic adenosine monophosphate (cAMP) measurements before and after alcohol intake (blood alcohol 1.5 per thousand), during hangover, and after a standardized bicycle exercise test. The beta-adrenoceptor density in lymphocytes was unchanged in the control group after alcohol intake or during hangover. Each of the AF patients had an increase in beta-adrenoceptor density after ethanol drinking (mean increase 29%, p <0.05). The hangover or exercise beta-receptor values did not differ from those in corresponding controls. Plasma adrenaline concentration tended to decrease and noradrenaline to increase after drinking and during hangover in both groups. Plasma cAMP levels were lower in patients after drinking than in controls (p <0.05). The exercise values of the adrenergic parameters were very similar in AF patients whether or not preceded by alcohol. Analysis of ambulatory electrocardiography showed a very low rate of ectopic beats in both AF patients and controls. Analysis of heart rate variability revealed a tendency toward an increase in sympathetic/parasympathetic component ratio (low-frequency/high-frequency ratio) in AF patients, but not in controls, after ethanol drinking. In conclusion, no signs of arrhythmogenic cardiac disease were detected in patients with AF to explain the tendency toward AF. Increases in beta-adrenoceptor density and low-frequency/high-frequency ratio during ethanol intoxication in patients with AF suggest an exaggerated sympathetic reaction.

Adrenergic beta-Agonists↗
PubMed1998

Regulation of cardiac myocyte contractile function by inducible nitric oxide synthase (iNOS): mechanisms of contractile depression by nitric oxide.

Inflammatory cytokines have been implicated in the reversible depression of cardiac contractile function accompanying local or systemic immune stimulation. Incubation of cardiac myocytes with soluble components in the supernatant from cultured rat lung macrophages activated with endotoxin decreases their contractile response to beta-adrenergic stimulation through the induction of iNOS and the subsequent production of nitric oxide by these cells. In the present study, we characterize the mechanisms underlying NO's attenuation of adrenergic responsiveness in cardiac myocytes. iNOS was induced in cultured ventricular myocytes from adult rats by incubation for 20 h with conditioned medium from lipopolysaccharide (LPS)-activated macrophages. iNOS induction did not induce any alteration in beta-adrenergic receptor density or affinity, Galphai protein abundance, or adenylyl cyclase activity in cultured myocytes. Myocyte exposure to activated macrophage-conditioned medium markedly attenuated the elevation of cAMP in response to isoproterenol (Iso, 2 nM). Induction of iNOS with the macrophage-conditioned medium also potentiated the Iso-induced increase in myocyte cGMP. This cGMP increase was totally abolished by NOS inhibitors. NOS inhibition also returned the attenuated cAMP response to 2 nM Iso to levels observed in control cells. Pre-incubation of the cells in isobutylmethylxanthine (IBMX), a phosphodiesterase inhibitor, also partly reversed the attenuation of cAMP increase with 2 nM Iso in cells expressing iNOS. Brief (15 min) exposure of myocytes to the NO donor, S-nitrosoacetylcysteine (SNAC, 100 micro M) which produced a three-fold increase in intracellular cGMP, also decreased by half the contractile response of cardiac myocytes to Iso (2 nM). We conclude that NO endogenously produced by iNOS decreases the intracellular levels of cAMP in response to beta-adrenergic stimulation in isolated cardiac myocytes, in part through a cGMP-mediated mechanism. This effect may participate in the NO-dependent depression of cardiac function following cytokine exposure.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Role of transiently altered sarcolemmal membrane permeability and basic fibroblast growth factor release in the hypertrophic response of adult rat ventricular myocytes to increased mechanical activity in vitro.

One of the trophic factors that has been implicated in initiating or facilitating growth in response to increased mechanical stress in several tissues and cell types is basic fibroblast growth factor (bFGF; FGF-2). Although mammalian cardiac muscle cells express bFGF, it is not known whether it plays a role in mediating cardiac adaptation to increased load, nor how release of the cytosolic 18-kD isoform of bFGF would be regulated in response to increased mechanical stress. To test the hypothesis that increased mechanical activity induces transient alterations in sarcolemmal permeability that allow cytosolic bFGF to be released and subsequently to act as an autocrine and paracrine growth stimulus, we examined primary isolates of adult rat ventricular myocytes maintained in serum-free, defined medium that were continually paced at 3 Hz for up to 5 d. Paced myocytes, but not nonpaced control cells, exhibited a "hypertrophic" response, which was characterized by increases in the rate of phenylalanine incorporation, total cellular protein content, and cell size. These changes could be mimicked in control cells by exogenous recombinant bFGF and could be blocked in continually paced cells by a specific neutralizing anti-bFGF antibody. In addition, medium conditioned by continually paced myocytes contained significantly more bFGF measured by ELISA and more mitogenic activity for 3T3 cells, activity that could be reduced by a neutralizing anti-bFGF antibody. The hypothesis that transient membrane disruptions sufficient to allow release of cytosolic bFGF occur in paced myocytes was examined by monitoring the rate of uptake into myocytes from the medium of 10-kD dextran linked to fluorescein. Paced myocytes exhibited a significantly higher rate of fluoresceinlabeled dextran uptake. These data are consistent with the hypothesis that nonlethal, transient alterations in sarcolemmal membrane permeability with release of cytosolic bFGF is one mechanism by which increased mechanical activity could lead to a hypertrophic response in cardiac myocytes.

Animals↗
PubMed1996

Effect of beta-blocking agents with and without intrinsic sympathomimetic activity on work efficiency in healthy men.

In order to evaluate the effect of beta-blocking agents with and without intrinsic sympathomimetic activity (ISA) on work efficiency in healthy subjects, we studied the haemodynamic and gas exchange parameters, as well as blood lactate concentrations, during a graded maximal bicycle exercise test performed after perorally given propranolol (PRO) and pindolol (PIN) in seven healthy men. The medications (PRO: 80 mg x 2/day, PIN: 10 mg x 2/day, for seven days) were given in a placebo (PLA) controlled, double-blind, randomized, cross-over fashion. Both the drugs reduced heart rate and blood pressure during exercise equally compared with the placebo. The oxygen uptake at submaximal work loads, as well as at the maximum, was constantly and equally reduced by PRO and PIN compared with PLA. The anaerobic threshold was reached at a slightly lower oxygen uptake for both the drugs compared with the placebo (P < 0.05). No significant difference was, however, observed in the work levels at which the ventilatory anaerobic threshold was reached. Moreover, the gross efficiency, i.e. the amount of work performed at a certain energy consumption level (aerobic + anaerobic), was increased by both PRO (26.7 +/- 0.5%, P < 0.02 vs PLA: 24.7 +/- 0.5%) and PIN (26.5 +/- 0.5%, P < 0.05 vs PLA) at a submaximal work load of 240 W. The results indicate that beta-blocking agents propranolol and pindolol slightly and equally reduce maximal work performance, but increase the efficiency of submaximal work in a way that a certain amount of external work can be done with smaller consumption of oxygen. These findings may contribute to the benefit of beta-blocking agents in patients with coronary heart disease.

Adrenergic beta-Antagonists↗
PubMed1994

Regulation of heparin-binding epidermal growth factor-like growth factor mRNA levels by hypertrophic stimuli in neonatal and adult rat cardiac myocytes.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a recently characterized member of the EGF family of peptide signaling factors that acts as an early response gene to growth stimuli in vascular smooth muscle cells, as well as being a potent mitogen for these cells. As many of these growth stimuli also induce a hypertrophic response in heart muscle, we examined the regulation of HB-EGF mRNA abundance and function in primary cultures of neonatal rat ventricular myocytes and adult rat ventricular myocytes (ARVM). HB-EGF mRNA levels increased 40- and 6-fold in neonatal rat ventricular myocytes and ARVM, respectively, following a 2-4-h exposure to the alpha-adrenergic agonist phenylephrine, a known hypertrophic stimulus for these cells. Phenylephrine had no effect on HB-EGF mRNA stability, and induction of HB-EGF could be blocked completely by actinomycin D. HB-EGF mRNA abundance was also increased 15-fold in ARVM maintained in defined medium that had been induced to contract at 3 Hz by continual uniform electric field stimulation, a mechanical stimulus that we have shown preserves contractile function and induces cell growth in vitro. To determine whether cardiac myocytes would respond to exogenous HB-EGF, quiescent ARVM were exposed to defined medium conditioned by transfected COS MT cells overexpressing HB-EGF. These myocytes exhibited nearly a 2-fold increase in protein content at 24 h compared with unstimulated control ARVM exposed to medium conditioned by COS cells transfected with the plasmid vector alone. Thus, neonatal and adult cardiac muscle cells respond to both neurohumoral and mechanical growth stimuli with a marked increase in HB-EGF mRNA, which may act as an early response gene to facilitate hypertrophic growth in these cells.

Age Factors↗
PubMed1992

Beta-adrenergic system in myotonic dystrophy.

Myotonic dystrophy (DM) is considered an inherited membrane disorder, but the basic defect is unknown. We studied plasma catecholamines as well as lymphocyte and muscle beta-adrenergic receptor densities and functioning in 19 DM patients and 15 control subjects. Plasma adrenaline and noradrenaline concentrations were not significantly different between DM patients and controls. In isolated lymphocytes basal cAMP production was 157 +/- 26 pmol/mg protein/10 min in DM patients and 91 +/- 12 pmol/mg protein/10 min in controls (n.s.), whereas isoproterenol-stimulated cAMP production was significantly higher in DM patients (285 +/- 42 pmol/mg protein) compared with control subjects (168 +/- 21 pmol/mg protein, P less than 0.05). Lymphocyte beta-adrenoceptor densities were similar among DM patients (50 +/- 3 fmol/mg protein) and controls (47 +/- 5 fmol/mg protein). beta-Adrenoceptor densities were also similar in muscle biopsy specimens (12.9 +/- 1 in DM and 13.1 +/- fmol/mg protein in controls). The correlation between lymphocyte and skeletal muscle receptor densities was r = 0.35 in DM patients and r = 0.22 in controls. The results do not support the hypothesis of adrenergic dysfunction in DM despite its membrane involvement.

Adolescent↗
PubMed1992

Expression and function of beta-adrenergic receptors in human hematopoietic cell lines.

We investigated the expression and functional characteristics of beta-adrenoceptors in a panel of 10 phenotypically different human hematopoietic cell lines. A binding assay with [125I]iodocyanopindolol as the ligand revealed that cell lines of myelomonocytic or histiocytic derivation (HL-60, ML-2, RC-2A, U-937) expressed high numbers of beta-adrenoceptors. An intermediate density of receptors was found in a non-T, non-B cell leukemia line (Nall-1), whereas T-cell (JM, CCRF-CEM), B-cell (Raji) or erythroleukemic cell lines (K-562, HEL) displayed minimal or undetectable binding of the radioligand. Isoprenaline-stimulated cAMP production by the cells correlated to their extent of beta-adrenoceptor expression. Southern blot hybridization analysis of genomic DNA from the cell lines with a 32P-labelled beta 2-adrenoceptor cDNA probe revealed no evidence for major rearrangement or amplification of the receptor gene. Incubation with isoprenaline in vitro suppressed the proliferation of the receptor-rich RC-2A cells but did not affect the growth rate of the receptor-deficient K-562 cells. Treatment with propranolol slightly enhanced the proliferation of the RC-2A cells but did not markedly alter the growth rate of two other cell lines, regardless of their beta-adrenoceptor status. These findings indicate a regulatory influence by the sympathoadrenergic system on selected cells of the myelomonocytic lineage.

Blood Cells↗
PubMed1991

Physical exercise after alcohol intake: effect on plasma catecholamines and lymphocytic beta-adrenergic receptors.

The combined effects of alcohol intoxication and intense physical exercise on the adrenergic system were studied in eight healthy male volunteers. Ethanol (0.8 g/kg body weight) was administered perorally to bring about a mean serum concentration of 21 mmol/liter (0.1%); each subject also participated in an identical control session without alcohol. Acute alcohol intake alone did not change the concentrations of plasma adrenaline or noradrenaline or the density, affinity, and functioning (ability to mediate catecholamine-stimulated production of cAMP) of lymphocytic beta-adrenergic receptors. In contrast, acute ergometer exercise brought about an approximately 10-fold increase of plasma adrenaline and noradrenaline concentrations, a 2- to 3-fold increase of beta-adrenergic receptor density and an enhancement of isoproterenol-stimulated cAMP production. Alcohol intake immediately before the ergometer exercise did not modify these changes. In conclusion, acute physical exercise activates the human adrenergic system, with an increase of both plasma catecholamines and lymphocytic beta-adrenergic receptors. Moderate alcohol intoxication does not affect exercise-induced alterations of these parameters.

Adult↗
PubMed1990

Effect of propranolol and pindolol on the up-regulation of lymphocytic beta adrenoceptors during acute submaximal physical exercise. A placebo-controlled double-blind study.

The effect of beta-adrenoceptor antagonists, with and without intrinsic sympathomimetic activity, on the regulation of lymphocytic beta adrenoceptors during acute physical exercise was studied. Seven healthy volunteers underwent a graded maximal ergometer test after treatment for 7 days with placebo, propranolol (2 x 80 mg/day), or pindolol (2 x 10 mg/day). Each subject received the three types of drug treatment in a double-blind, randomized fashion, with 3 weeks wash-out periods between the on-drug periods. The mean resting density of lymphocytic beta adrenoceptors was 46 +/- 5 fmol/mg protein (mean +/- SEM) during placebo, 53 +/- 5 fmol/mg protein during propranolol, and 29 +/- 4 fmol/mg protein during pindolol treatment (p less than 0.05, pindolol vs. propranolol). Exercise induced a significant up-regulation of the beta-adrenoceptor density during each treatment modality, but the increment was attenuated during propranolol (mean elevation, 16 +/- 2 fmol/mg protein, p less than 0.05) and pindolol intake (13 +/- 4 fmol/mg protein, p less than 0.02) as compared with the placebo value (56 +/- 13 fmol/mg protein). Moreover, exercise-induced increment of lymphocytic cyclic AMP (cAMP) production was virtually abolished by the two beta-adrenoceptor antagonists. In conclusion, administration of beta-adrenoceptor antagonists is associated with a subnormal up-regulation of the lymphocytic beta-adrenoceptors and alterations in their functioning during heavy physical effort. This attenuation is not modified by intrinsic sympathomimetic activity of the compound.

Adult↗