Search PubMed⌕ Search

Biomedical subjects

J Lorenc

Publications and source records attributed to J Lorenc.

At least 19 recordsLinked to original sources
PubMed2005

Vibrational spectra and chemical quantum calculations for 2-adamantylamino-5-nitropyridine crystals--a novel material for laser Raman converters.

Polycrystalline infrared and polarized FT-Raman spectra have been measured for 2-adamantylamino-5-nitropyridine, a novel organic material for laser Raman converters. The assignment of IR and Raman bands is given on the basis of DFT calculations. The spectroscopic studies have not indicated the presence of any significant intermolecular interactions in the crystal structure of this compound. The lines observed in the stimulated Raman spectrum of this crystal are assigned to the respective molecular vibrations.

Adamantane↗
PubMed2005

[Assessment of the incidence of metabolic syndrome].

BACKGROUND: Metabolic syndrome represents a disease with high prevalence and influence on the cardiovascular morbidity and mortality. The aim of this study is to estimate frequency of metabolic syndrome in the district Sumperk, in years 1979-1981 based on the analysis of large Preventive check-ups database. METHODS AND RESULTS: Database of Preventive oncologic check-ups from Sumperk district comprising 40 099 subjects with follow up in years 1979-1981 has been used to assess the metabolic syndrome prevalence. Incidence of the risk factors of the metabolic syndrome have been calculated and compared with current situation in the Czech Republic. The estimated incidence of metabolic syndrome ranged from 2.2% to 8.4%, according to the selected criteria. As risk factors diabetes type II or glycaemia higher than 6.1 mmol/l, systolic or diastolic hypertension and BMI higher than 30.0 kg/m2 were considered. It has been found that metabolic syndrome is increasing with increasing age in both male and female population. CONCLUSIONS: It is possible to assume, based on the results of this study that the incidence of the metabolic syndrome is increasing in the last decades. It is necessary to focus our attention on the simple and practical methods for early detection of metabolic syndrome. Important is also the prevention because metabolic syndrome plays important role as a predictor of serious cardiovascular and metabolic diseases.

Adult↗
PubMed2004

[Risk factors for tumors, cardiovascular and metabolic diseases in the population of the Sumperk District].

BACKGROUND: Cardiovascular diseases and cancers are responsible for almost 80% of the total mortality in the Czech Republic. For their prevention, identification of risk factors becomes indispensable. Presented article analyses frequency of risk factors in the population of Sumperk district on the bases of the first and second preventive oncological check-ups. METHODS AND RESULTS: Diagnoses have been unified according to the International Classification of Diseases. For data analysis SPSS statistical software has been used. Frequency of obesity, hypertension, hyperglycemia, hypercholesterolemia, hyperuricemia and smoking has been assessed in subjects during their first and second preventive check-ups. In the course of the first check-up 49,426 subjects have been examined, out of them 22,857 males (46.2%) and 26,569 females (53.8%). 40,386 subjects participated in the second check-up (18,378 males and 22,008 females). The assessment of the frequency of the individual risk factors has been done on the bases of the examination results. CONCLUSIONS: Total incidence of obesity was lower in males comparing to the data from the population of 6 districts of the Czech republic (MONICA). Due to the treatment of subjects, there was a mild decrease of prevalence of the systolic hypertension in the second check-up in comparison with the first one. In comparison with MONICA project, the incidence of hypertension was more than twice higher. No difference in frequency of hyperglycemia in males and females was found. In both genders, high prevalence of hypercholesterolemia (about 70%) was found. Between two check-ups, decrease of hypercholesterolemia prevalence was observed. It corresponds with the existing trend in the Czech population. Decrease of smoking prevalence has been observed in the second check-up mainly in males and less in females. In comparison with MONICA project, there was a higher smoking prevalence in males and a lower one in females.

Adult↗
PubMed2002

Multinuclear 1H, 13C and 15N NMR study of some substituted 2-amino-4-nitropyridines and their N-oxides.

1H, 13C and 15N NMR chemical shift assignments based on pulsed field gradient selected PFG 1H,X (X = 15C and 15N) HMQC and HMBC experiments are reported for three 4-nitropyridine N-oxides and four 4-nitropyridines. It was found that an ortho effect of a methyl group inhibits the deshielding effect of the 4-nitro group and that this effect and the so-called back donation is influenced by electronegativity and position of substituents in the multisubstituted pyridine N-oxides. The shielding effect of N-oxide group is most pronounced in the 15N NMR chemical shifts of the studied compounds. This effect is further modified by methylamino, methylnitramino, 5- or 3-methyl and 4-nitro groups. Among them the 4-nitro group exerts the highest influence on the shielding effect of the N-oxide functionality. Experimental 1H, 13C and 15N NMR chemical shifts and GIAO/DFT theoretical calculations are consistent with each other and supported by the reactivity on nucleophilic substitution, the UV spectral and the dipole moment data.

Carbon↗
PubMed2001

Bone turnover rate in postmenopausal women: bimodal distribution?

There is considerable evidence that elevated bone turnover is an independent form of low bone mineral density (BMD) risk factor of osteoporotic fractures. The aim of our study was to test whether a group of postmenopausal women could be divided into subgroups of high and low bone turnover rate using different pairs of bone turnover markers (one resorption, one formation). Cluster analysis was used to obtain high and low bone turnover subgroups within the study group. A magnitude of difference in lumbar spine BMD (expressed as Z-score) between high- and low-turnover groups was used as a criterion of division success. According to this criterion, the division obtained with a urinary type I collagen crosslinked N-telopeptide/bone alkaline phosphatase pair of markers appeared to be the most significant. This method of separation of two subgroups was highly concordant with the division based on the upper thresholds of the normal values for those markers found for the premenopausal women. It seems that the observed existence of high-and low-turnover subject clusters is not an incidental phenomenon, because the effects obtained for the whole study group were further confirmed by the consistent results of cluster analysis, performed separately for two randomly selected subgroups (A and B) from the study group. The results obtained appear to support the view that bone turnover rate in postmenopausal women is distributed in the bimodal fashion. This finding seems to justify further investigations of more elaborated models, enabling clinicians to individually classify their patients as low- or high-turnover cases with higher efficiency, as in the case of cutoff values for single markers.

Aged↗
PubMed2000

Response of aorta connective tissue matrix to injury caused by vassopressin-induced hypertension or hypercholesterolemia.

The aim of the study was to investigate the effect of two various atherogenic stimuli (vasopressin-induced hypertension or hypercholesterolemia) on the collagen and glycosaminoglycan (GAG) content in the internal or external part of both thoracic and abdominal aorta, which are differently susceptible to atherosclerosis. Experimental rabbits were divided into four groups: controls, animals injected with physiological saline or vasopressin at the dose of 1 IU/kg from the 1 st to the 25 th day of experiment, respectively. The animals from group 4 were maintained on food, containing 0.25% cholesterol. Only in the vasopressin-treated group, the systolic blood pressure was elevated from 110 mmHg at the beginning, to 166 mmHg at the end of the study. After 14 weeks the aorta was dissected into internal and external parts. GAG fractions were separated and estimated as uronic acids. Collagen was evaluated as the hydroxyproline content in the tissue. Augmented total GAG and heparan sulphate (HS) level, plus no changes in the collagen content were seen in the internal part of the thoracic aorta in rabbits with hypercholesterolemia or hypertension. In the hypertensive animals, the changes were extended to the external part of the aorta and, additionally, comprised the elevation of the chondroitin-4 sulphate (C-4S) content. The two atherogenic stimuli increased the collagen level with no elevation of the GAG content in the abdominal aorta. A convergent effect of the injury, caused by hypertension or hypercholesterolemia on the collagen, total GAG and HS content was shown in the respective parts of the rabbit aortas. The common GAG, increased in the thoracic aorta, stand for the HS, in both hypertensive and hypercholesterolemic rabbits. As the sensitivity to atherosclerosis development in different segments of the aorta varies, they express various responses of the connective tissue matrix to injuries, caused by hypertension or hypercholesterolemia.

Animals↗
PubMed1989

[Disorders of lipid and lipoprotein metabolism in patients with chronic lymphocytic leukemia. I. Preliminary evaluation of lipemia and HDL fractions in various stages of the disease].

The study comprised 128 patients with chronic lymphocytic leukemia (CLL) aged 65.7 +/- 8 years, 59 women and 69 men. Among the patients studied 70 were treated and 58 yet not underwent therapy. The Rai classification of patients with CLL has been used. The control group consisted of 68 subjects aged 56.8 +/- 14 years, 35 women and 33 men, showing no diseases affecting the blood lipid disturbances. The following determinations have been performed in the blood serum: apo B, CH, TG, PL, and CH or PL in the isolated HDL fraction; LDL-CH ratio has also been calculated. In patients with CLL the total CH concentration has been noted which advanced parallel to the disease progress. It resulted first of all from the decrease in LDL-CH (p less than 0.05). Similar alterations have been noted so far as apo B is concerned. It has been demonstrated that the decrease in HDL-CH (p less than 0.05) is also dependent on the disease stage. The simultaneously increasing index HDL-PL/HDL-CH indicate on changes within the HDL2 and HDL3 subfractions suggesting a deficiency of the HDL2 subfraction. The total lipemia and the lipoprotein fraction alterations observed make the diagnostic value of the atherosclerotic threat in patients with CLL doubtful with the use of that parameters.

Aged↗
PubMed1989

[Serum lipids and lipoproteins in patients with cerebrovascular disorders].

In 150 patients with cerebral insult and in 153 subjects of the control group the studies have been performed with an aim to establish the biochemical evaluation of the arteriosclerotic threat. The cholesterol, phospholipid, triglyceride and apo B concentration in the serum as well as quantitative evaluation of the HDL and LDL fractions were involved. The sex-related differences have been found so far as apo B and lipid serum components are concerned. The most characteristic alterations have been showed in the HDL fraction. In the all patients studied the significant decrease in the HDL-CH concentration as well as an increased HDL-PL/HDL-CH index has been noted suggesting changes in the HDL subfraction leading to the diminished concentration of anti-atherogenic HDL2 fraction.

Adult↗
PubMed1989

[Blood lipid and lipoprotein profile in patients in the first week of myocardial infarction].

The serial enzymatic and lipid determinations have been performed in 30 patients with myocardial infarction during the first 6 to 7 days of the disease. During the phase of myocardial infarction development paralel to increasing creatine kinase (CK) activity the increase in the cholesterol (CH) and phospholipid (PL) as well as the increase of HDL and LDL serum fraction (p less than 0.0005) has been observed. At the end of the second day the CK activity normalization has been accompanied by the gradual decrease in the HDL and LDL fraction concentration up to values lower than that at the start of observation (p less than 0.0005). The HDL-PL/HDL-CH coefficient enables the evaluation of changes in the subfraction HDL during the first days of myocardial infarction consisting of HDL2 concentration decrease. Above changes indicate the progressive arteriosclerosis of coronary arteries despite lowering the total CH and the LDL-CH concentration in the serum of patients with acute myocardial infarction.

Adult↗