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Biomedical subjects

M Zeman

Publications and source records attributed to M Zeman.

At least 37 records · Page 2Linked to original sources
PubMed1996

[The effect of fish oil on metabolic parameters in patients with type 2 diabetes mellitus associated with dyslipidemia].

BACKGROUND: The authors discuss the effect of administration of fish oils rich in n-3 fatty acids in diabetic patients type 2 and draw attention to the possible deterioration of glucose homeostasis. The objective of the investigation was to assess changes of the lipid and carbohydrate metabolism in type 2 diabetics with associated dyslipidaemia after enrichment of the diet with n-3 fatty acids. METHODS AND RESULTS: To 17 patients with type 2 diabetes and dyslipidaemia fish oil containing 5.5 g n-3 fatty acids per day was administered. After six weeks a decline of triglycerides was recorded (-47%, P < 0.01), free fatty acids (-27%, P < 0.01) and a rise of HDL2-cholesterol (25%, P < 0.05). The concentration of apo B, apo A-1, LDL- and HDL cholesterol did not change significantly. There were no significant changes of the blood sugar level, glycosylated haemoglobin and fructosamine. The insulin and C-peptide concentration on fasting (and after glucagon stimulation) did not change significantly. With regard to the HDL2-cholesterol and 18:0 fatty acid concentration in serum the group can be divided into responders (with a decline of glycosylated haemoglobin) and non-responders. The two groups have a reverse trend of blood sugar levels and insulinaemia and differ as to the metabolism of 18:1 n-7 acid. CONCLUSIONS: Enrichment of the diet with n-3 fatty acids in diabetics with dyslipidaemia has a favourable effect on the plasma lipid spectrum without causing deterioration of parameters of diabetes compensation. Among the group of patients some can be found where fish oil administration improves also glucose homeostasis.

Blood Glucose↗
PubMed1996

Plasma thyroid hormone and growth hormone patterns in precocial Japanese quail and altricial European starlings during postnatal development.

Plasma concentrations of thyroid hormones (TH) and growth hormone (GH) during postnatal development in the precocial Japanese quail (Coturnix japonica), and the altricial European starling (Sturnus vulgaris) were measured. Developmental changes in plasma TH found in the starling, differ considerably from those detected in quail. In quail rather high triiodothyronine (T3) values were measured during the first few days after hatching. Subsequently a steady decrease of plasma T3, to adult levels, was observed. Thyroxine (T4) concentrations did not change significantly during the period studied. In starlings, on day 1, plasma T3 was low and T4 was at or below the assay detection limit. An increase in concentrations of both hormones occurred between day 1 and day 5 after hatching. A gradual increase of T4 occurred afterwards, while plasma T3 levels remained nearly constant during this growing period. Plasma GH concentrations showed a similar pattern in both species. There was an increase during first days after hatching and GH concentrations peaked at day 7 in quail and day 5 in starlings. A subsequent decrease was observed in both species. Although the GH profiles in species studied were comparable, there were noticeable differences in their growth rates. Thus different developmental strategies have been reflected in different developmental patterns of TH in precocial Japanese quail and altricial European starling whereas developmental changes of GH levels were similar in both species.

Aging↗
PubMed1996

Effect of recombinant human insulin-like growth factor-II on weight gain and body composition of broiler chickens.

Osmotic minipumps containing either saline or recombinant human insulin-like growth factor-II (IGF-II) were implanted into 4-wk-old female broiler chickens such that the treated chickens received 0.5 mg IGF-II/kg body weight per d. At the end of the trial, no differences in body weight gain or bone length were detected between the treated and control groups. Similarly, there were no differences between the two treatments with respect to heart, spleen, liver, or bursa of Fabricius weight. The relative weight of the abdominal fat pads was greater (P < 0.05) in the birds treated with IGF-II than in the controls, whereas the weight of breast muscle was reduced (P = 0.06) in the birds treated with IGF-II. There was no effect of IGF-II treatment on feed intake or feed conversion efficiency. Plasma growth hormone (GH) levels were acutely depressed by 15 min after IGF-II administration; and also after 2 wk of IGF-II treatment. Plasma triiodothyronine (T3) concentrations were significantly depressed by IGF-II treatment. These results suggest that IGF-II may not stimulate growth in chickens, but can act as a nutrient partitioning agent, either directly or indirectly through altering plasma GH or T3 concentrations.

Adipose Tissue↗
PubMed1995

Development of rhythmic melatonin synthesis in cultured pineal glands and pineal cells isolated from chick embryo.

The chick pineal gland exhibits circadian rhythms in melatonin synthesis under in vivo and in vitro conditions. A daily rhythm of melatonin production was first detectable in pineal glands isolated from chick embryos at embryonic day 16 and incubated under a LD cycle. All pineal glands isolated from 17-day-old and older embryos were rhythmic while no gland isolated at embryonic day 14 and 15 exhibited a daily rhythm in melatonin synthesis. Melatonin production in static cultures of embryonic pineal cells was rhythmic over 48 h if the cells were kept under a LD cycle. When embryonic pineal cells were incubated in constant darkness the rhythm in melatonin production was damped within 48 h. These results suggest that chick pineal cells from embryonic day 16 onwards are photosensitive but that the endogenous component of the melatonin rhythm is not completely developed at that age. A soluble analogue of cAMP stimulated and norepinephrine inhibited melatonin synthesis in cultured embryonic pineal cells. These findings indicate that the stimulatory and inhibitory pathways controlling melatonin synthesis in the mature pineal gland are effective in pineal cells isolated from chick embryos at least 2 days before hatching.

Age Factors↗
PubMed1995

[Indicators of lipoprotein metabolism in normolipemic men after myocardial infarct].

BACKGROUND: In some patients with ischaemic heart disease disorders of the lipoprotein metabolism were found although the plasma cholesterol and triglyceride levels were not elevated. The objective of the present work was to assess parameters of the lipoprotein metabolism which could differentiate normolipidaemic probands with an increased risk of myocardial infarction. METHODS AND RESULTS: The authors examined a group of 21 men with normal values of plasma cholesterol and triglycerides who had suffered 6 months to 3 years ago from a myocardial infarction. As compared with a control group of normolipidaemic men without evidence of ischaemic heart disease, these patients had significantly lower HDL-C concentrations (-22%, p < 0.01), in particular due to a lower sub-fraction HDL,-C (-29%, p < 0.001), a higher apolipoprotein B concentration in LDL (+36%, p < 0.00) and a lower value of the cholesterol/apolipoprotein B ratio in LDL (-25%, p < 0.05). The total cholesterol, triglyceride, LDL cholesterol, HDL2-cholesterol, apolipoprotein A-1 concentration and cholesterol/apolipoprotein A-1 ratio in HDL did not different significantly. The method of discrimination analysis revealed that for the differentiation of the two groups assessment of apolipoprotein B in LDL and HDL3-C are most useful. By this approach 80% of the patients in the group were correctly classified. CONCLUSIONS: The results of the presented work confirmed the importance of assessment of apolipoprotein B and HDL-C, incl. its sub-fractions for estimating the risk of ischaemic heart disease in normolipidaemic subjects.

Humans↗
PubMed1995

Endogenous gonadal, LH and molt rhythms in tropical stonechats: effect of pair bond on period, amplitude, and pattern of circannual cycles.

To investigate the effects of reproduction and associated stimuli on the circannual cycles of African stonechats Saxicola torquata axillaris birds were held for 29 months in aviaries under a constant equatorial (12.25 h) photoperiod, either singly (10 females and 10 males) or in 10 male/female pairs. The birds of all 3 groups went through circannual cycles in gonadal size, plasma LH and molt, but groups differed with regard to actual reproductive performance. During the second cycle, only one of the singly-held females laid eggs and incubated. In contrast, in the paired females egg-laying and incubation occurred in all but one bird. About 50% of the clutches from paired females contained fertilized eggs confirming the expectation of behavioral differences between the paired and unpaired birds. However, despite differences in reproductive performance there were no differences in either circannual period or duration of reproductive phases. Moreover, there was no correlation between number of broods produced per season and circannual parameters of the paired females. Therefore, the temporal course and, particularly, the period during which reproduction is possible is rigidly determined by an endogenous program that is not influenced by reproductive performance. A rigid program of this kind may be advantageous in the tropics because it prevents prolongation of the breeding season in years with favourable conditions which in turn could jeopardize optimal timing of breeding in the following year and thus reduce lifetime reproductive success.

Africa↗
PubMed1995

Passive immunization of insulin-like growth factor (IGF)-1 and of IGF-1 and IGF-2 in chickens.

The effects of passive immunization against IGF-1 either alone, or together with immunization against IGF-2, on growth and metabolism were examined in chickens. Immunization against IGF-1 alone had no effect upon any aspect of growth, carcass composition, efficiency of energy utilization or hormone concentrations studied. Immunization against both IGF-1 and IGF-2 together resulted in a lighter final body weight (P < 0.05) compared with controls. Immunization against both IGFs together decreased abdominal fat content (P < 0.05) and resulted in a heavier mean spleen weight (P < 0.01). The joint immunization was also associated with elevated plasma T3 concentrations. These data may indicate a role for IGF-2, but not for IGF-1, in fat metabolism in chickens.

Adipose Tissue↗
PubMed1995

[The effect of polyene phosphatidylcholine administration on lipid metabolism and glucose tolerance in patients with hyperlipoproteinemia IIB].

BACKGROUND: Up to now, clinical and experimental studies have brought only inconsistent data about the effectiveness of polyene phosphatidylcholine (PPC) in treatment of dyslipidemia. The aim of this randomized, double blind study was to verify the effects of the polyene phosphatidylcholine preparation Lipostabil forte R (Rhone-Poulenc-Röhrer, Köln, FRG), given orally in a daily dose 2.7 g for three months to patients with hyperlipoproteinemia type IIB and hypoalfacholesterolemia both on the plasma lipids, lipoproteins, apolipoproteins and the parameters of glucose tolerance. METHODS AND RESULTS: Administration of PPC to 30 patients with hyperlipoproteinemia type IIB and hypoalfacholesterolemia led to a significant rise of HDL-cholesterol, HDL3-cholesterol and plasma apolipoprotein A-I concentrations in comparison with the group treated with placebo. At the same time, plasma apolipoprotein B concentration slightly increased. Blood glucose, immunoreactive insulin and non-esterified fatty acid concentrations during the oral glucose tolerance test didn't change significantly after PPC administration. CONCLUSIONS: It seems PPC could be the appropriate supplement to the treatment of patients with decreased concentrations of HDL-cholesterol and plasma apolipoprotein A-I.

Double-Blind Method↗
PubMed1995

Indices of plasma lipoprotein metabolism in normolipidemic myocardial infarction survivors.

BACKGROUND: Many patients suffering from ischaemic heart disease (IHD) were shown to be characterized by different deviations of lipoprotein metabolism without having plasma cholesterol and triglyceride levels increased. The aim of the study was to determine the parameters of lipoprotein metabolism most contributing to finding among normolipidemic men those with an elevated risk of myocardial infarction. METHODS AND RESULTS: We investigated 21 men with normal plasma cholesterol and triglyceride levels, who survived myocardial infarction (MI) in the period 6 months to 3 years before the investigation (group MI). In comparison with the control group of normolipidemic men without IHD, survivors of MI had significantly lower concentrations of HDL-C (-22%, P < 0.01), especially in HDL3 subfraction (-24%, P < 0.001), higher concentrations of apo B in LDL (+36%, P < 0.001) and lower values of cholesterol to apo B ratio in LDL (-25%, P < 0.05). The concentrations of total plasma cholesterol, triglycerides, LDL-cholesterol, HDL2-cholesterol, apo A-I and the ratio HDL-C/apo A-I did not differ significantly. Discriminant analysis revealed that for separating the two groups, determining apo B in LDL and HDL3-C was most advantageous as thus 80% patients in this set could be correctly classified. CONCLUSIONS: These results show the significance of the investigation of apo B and HDL-C including their subfractionism HDL2 and HDL3 for the estimation of MI risk in normolipidemic men.

Humans↗
PubMed1994

[Comparison of the effects of omega-3 polyunsaturated fatty acids and Olbetam (Acipimox) in the treatment of hypertriglyceridemia].

BACKGROUND: Hypertriglyceridaemia associated with low HDL-concentrations is considered an independent risk factor of ischaemic heart disease. The drug of choice in this disorder is nicotinic acid. The aim of the presented work was to compare the hypolipidaemic effect of fish oils rich in omega-3 fatty acids (Activepa 30-TGR, Hydromartens, Norway) with a nicotinic acid derivative, acipimox (Olbetam, Farmitalia Carlo Erba, Italy). METHODS AND RESULTS: The preparations were administered for a three-week period to two groups of patients with hypertriglyceridaemia and low HDL cholesterol levels. The groups had comparable body weights and baseline parameters of lipid metabolism. In the group treated with Olbetam (750 mg/day), 17x hyperlipoproteinaemia type IV and 6x IIB) after treatment significant changes of the following parameters were recorded: triglycerides (-18%; P < 0.001), HDL cholesterol (+19%; P < 0.01), HDL2 and HDL3 cholesterol (+33%; +14%; P < 0.001, P < 0.01), apo B (+25%; P < 0.01), apo A-I (+7%; P < 0.01), ratio of apoB/A-I (+17%; P < 0.01). Furthermore, there was s drop of the atherogenic index (total cholesterol/HDL cholesterol) by 22% (P < 0.001). In the group of subjects (17x type IV and 8x type IIB) whose diet was enriched with omega-3 fatty acids (3.5 g/day), the following parameters changed significantly: triglycerides (-44%; P < 0.001), the atherogenic index (-23%; P < 0.001), HDL cholesterol (+11%, P < 0.01), HDL2 and HDL3 cholesterol (+13%, +17%; P < 0.01, P < 0.05). Changes of apo B, apo A-I concentrations and their ratios were not significant. Comparison of the effect of the two preparations on the investigated parameters revealed a more marked rise of the HDL cholesterol (P < 0.05), apo B (P < 0.01) concentrations and the apo B/-A-I ratio (P < 0.05) during Olbetam treatment. As to the action of the two preparations on further investigated parameters (total and LDL-cholesterol), no significant differences found. CONCLUSIONS: The assembled results indicate that enrichment of the diet with fish oil rich in omega-3 fatty acids has a hypolipidaemic effect comparable to acipimox. It is thus feasible to use fish oils as a drug of first choice in the treatment of hypertriglyceridaemia associated with a reduction of HDL cholesterol concentration.

Fatty Acids, Omega-3↗
PubMed1993

[Fatty acid composition of plasma lipids in hyperlipidemia associated with ischemic heart disease].

The authors compared plasma lipid and lipoprotein values and the fatty acid composition in plasma lipids of a group of 38 men with primary hyperlipoproteinaemia (HLP) type II B and IV with a history of myocardial infarction (IM) and in a control group of 63 men with the same type of HLP without a history of ischaemic heart disease (IHD). Hyperlipidaemic subjects after IM differed from controls by the apolipoprotein (apo) B concentration in LDL lipoproteins and by the composition of fatty acids in plasma phosphatidylcholine (PC) and triglycerides (TG). In the discriminating function which makes it possible in the given group of patients to classify correctly hyperlipidaemic subjects after IM and without detectable IHD the independent variables are apo-B concentration in LDL, apo-A-I in plasma, eicosapentaenoic acid in TG, gamma-linolenic acid in cholesterol esters and stearic and oleic acid in PC. These findings confirm the practical value of assessment of apolipoproteins for detection of hyperlipidaemic subjects with a specially high risk of IHD and indicate also the role of essential FA in the pathogenesis of IM.

Fatty Acids↗
PubMed1993

Effects of exogenous melatonin on some endocrine, behavioural and metabolic parameters in Japanese quail Coturnix coturnix japonica.

1. Melatonin administration in drinking water (5 micrograms/ml) to Japanese quail resulted in a 20-fold increase of plasma melatonin levels in comparison with the control, day time concentration (0.34 +/- 0.05 vs 6.88 +/- 1.10 nmol/l). 2. Plasma triiodothyronine levels increased (5.8 +/- 0.93 vs 7.97 +/- 0.64 nmol/l), corticosterone decreased (28.04 +/- 3.42 vs 15.96 +/- 2.56 nmol/l) and no significant changes were recorded in thyroxine concentration after the treatment. 3. A higher occurrence of sleeping and lower occurrence of pecking were found in melatonin treated quail. 4. Abdominal fat deposition as well as the content of total lipids in the breast muscle and triacylglycerols in plasma were decreased in treated birds indicating an inhibitory effect of melatonin on lipogenesis. 5. Melatonin increased RNA content in the breast muscle but did not affect plasma glucose concentration and body weight.

Animals↗
PubMed1993

A naturally occurring growth hormone receptor mutation: in vivo and in vitro evidence for the functional importance of the WS motif common to all members of the cytokine receptor superfamily.

To obtain an animal model for studying the role of the GH receptor (GHR) in growth and development, we analyzed a sex-linked dwarf (SLD) chicken strain (Leghorn) which exhibits phenotype similarities with a human genetic growth disorder, an autosomal recessive GH resistance condition (Laron dwarfism). Having previously demonstrated the responsibility of the human GHR gene in the Laron phenotype, we focused our analysis on the corresponding gene in SLD chickens. Sequencing of the whole coding region of the chicken GHR cDNA identified a G-to-T transversion segregating with the SLD phenotype and generating an isoleucine instead of a serine at position 199 within a highly conserved region close to the junction between the extracellular and transmembrane domains. This defect involves the last invariant amino acid of the WS-like motif (amino acid sequence WSXWS) common to all members of the cytokine receptor superfamily. Transfection of a mutated GHR cDNA containing this mutation into eukaryotic cells led to the synthesis of a receptor protein that displayed impaired plasma membrane expression and binding activity. These data define the molecular basis for the SLD phenotype and identify this strain as an interesting model for studying Laron dwarfism in humans; this animal model may also represent a system in which therapeutic strategies to promote growth can be evaluated. Finally, the nature of the molecular defect identified provides direct evidence for the functional importance of the WS motif in GHRs and related receptors.

Amino Acid Sequence↗
PubMed1993

[The effect of the spectrum fatty acids in plasma lipids on the hypolipidemic effect of fish oils in hyperlipidemic patients].

The authors administered to a group of 60 patients with primary hyperlipoproteinaemia (HLP) HLP type IIA 9, IIB 16, type IV 35 (fish oil) (Activepa 30TG) rich in eicosapentaenic acid (EPA, 20:5-n-3) and docosahexaenic acid (DHA, 22:6n-3). Administration of fish oil, 10 g per day, for a period of 21 days led to a decline of the total cholesterol by 9.8%, triglycerides (TG) by 39.5% and a rise of HDL-cholesterol (HDL-C) by 12.8%. The concentration of LDL-C, apo B, and apo A-I did not change significantly. The content of individual fatty acids (FA) in phosphatidyl choline (PC) cholesteryl esters (CE) and plasma TG before treatment was used as an independent variable for discrimination analysis in relation to dependent variables such quintile 1 (Q1) and Q2 on the one hand and Q4 and Q5 differences of the above mentioned parameters on the other hand. The drop of TG after ingestion of n-3 FA correlates indirectly with concentrations of PC 20:5n-3, TG 18:3n-3 and TG 20:4n-6. The content of 20:0 and 20:1 in PC and 18:0 in TG are related to the rise of LDL-C after treatment. The drop of apo B is associated with the PC 22:6n-3 concentration. The rise of HDL-C and apo A-I is positively associated with the concentration of 16:1n-7 in PC and TG and negatively with the CE 16:0 content. The rise of HDL-C after treatment is moreover negatively influenced by concentrations of PC 18:3n-6 and TG 20:3n-6.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Development of melatonin rhythm in the pineal gland and eyes of chick embryo.

A melatonin rhythm was observed in the pineals of 18-day-old chick embryos incubated under a light-dark regime of 18: 6 h. A low pineal melatonin content was found during the light phase of the day. Concentrations started to increase 2 h after dark onset and reached maximum levels after 4 h of darkness. The amplitude of the pineal melatonin rhythm increased considerably after 2 days and night-time concentrations in 20-day-old embryos were more than 5 times higher than in 18-day-old ones. Significant day/night differences in melatonin production were found both in pineals and eyes. Exposure of eggs to 1 h of light during the dark period decreased the high melatonin concentrations in the eyes but not in the pineals of the 20-day-old chick embryo. The results suggest that in this precocial bird at least part of the circadian system may already operate during embryonic life.

Animals↗
PubMed1991

[The importance of plasma lipids and apolipoproteins in the assessment of risk of myocardial infarction in the most common types of primary hyperlipoproteinemias].

In a group of 60 men after myocardial infarction (IM) with primary hyperlipoproteinaemia (HLP), type IIA, IIB and IV the authors revealed on comparison with a control group of 71 men with similar types of HLP where ischaemic heart disease (IHD) was not detected, significantly higher concentrations of total plasma cholesterol (TC), low density lipoproteins (LDL-C), apolipoprotein (apo)B in LDL; in the hyperlipidaemic subjects after IM the concentration of HDL-C was significantly lower as well as the ratio of cholesterol and apo-B in the LDL fraction. In patients with hypercholesterolaemia (HLP IIA and IIB) for estimation of the risk of IHD LDL-C, HDL-C and apo-B in LDL are useful. In patients with hypertriglyceridaemia (HLP IIB and IV) subjects with a history of IM have in addition to a higher concentration of apo-B in LDL a lower ratio of cholesterol to apo-B in LDL and in those with HLP IV also a lower plasma concentration of apo-A-I. By the discriminating function the variable of which is in HLP IIB the apo-B concentration in LDL and in HLP IV apo-B in LDL and apo-A-I in plasma in HLP IIB 77.8% subjects and in HLP IV 82.9% subjects with an increased risk of IHD can be detected.

Apolipoproteins↗