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Biomedical subjects

I David

Publications and source records attributed to I David.

At least 19 recordsLinked to original sources
PubMed2002

[Perioperative tachyarrhythmia].

Sudden onset of tachyarrhythmias in an operating theatre or an intensive care unit can be a frustrating experience for an attending physician and sometimes even for his patient, not only because of severity of patient's clinical state, but also for the mental stress loaded on him by collaborating surgeons. From that reason, a diagnosis and treatment of such condition should be intensive, simple, effective and safe for the patient. Increased activity of sympathoadrenal system is the main pathophysiological condition in the pathogenesis of perioperative arrhythmias that can provoke sinus tachycardia followed with a transient myocardial ischaemia and other deleterious effects. Sympathetic nervous system stability plays an important role in the prevention and treatment of perioperative arrhythmias. In this review article, the author highlights a basic electrophysiology and molecular pathophysiology of heart rhythm disturbances, and on the background of recent clinical studies he tries to propose a simplified therapeutic algorithm for treatment of these difficult states. Beta-blockers and group III, antiarrhythmics of Vaughan-Williams classification (amidarone) are recommended as the optimal remedies for the treatment of tachyarrhythmias in the perioperative period.

Humans↗
PubMed2002

[Benign stenoses of the large respiratory airways].

BACKGROUND: Benign stenoses of main respiratory pathways develop usually in patients after intubation or tracheostomy. Incidence of such states is not known, they are frequently diagnosed too late, and there are different views of their treatment. In order to contribute to the improvement of our knowledge of this serious impairment we followed prospectively all patients with this diagnose at our department since March 1998. METHODS AND RESULTS: The group of 31 patients with benign stenoses of non-tumorous origin diagnosed and treated at the TRN of the Teaching Hospital Motol in years 1998 to 2000 consisted of 24 males and 7 females, age median was 52 years. Stenosis was caused in 27 patients by intubation, in 4 patients by some other causes. At admission we performed in 30 patients electrocauterization and dilatation of stenosis, one patient was immediately indicated for surgery. Beside two cases we always achieved sufficient patency of stenosis and weighted indication to surgery. We sent for surgery 15 patients, 10 patients were permanently healed using methods of interventional bronchoscopy, including introduction of stent in 6 cases. From the remaining 6 patients, two of them are planned for resection of stenosis, four are inoperable from various reasons, and two died of causes not related to stenosis. CONCLUSIONS: Based on our experience we recommend as an optimal management of such patients is the dilatation or removal of stenosis and then always to consider resection of trachea. In inoperable cases methods of interventional bronchoscopy should be used. Authors recommend sending all patients intubated longer than 2 days for bronchoscopic examination in interval of 2 months.

Bronchial Diseases↗
PubMed2001

Stability of exploratory eye movements as a marker of schizophrenia--a WHO multi-center study. World Health Organization.

The exploratory eye movements of patients with schizophrenia reportedly differ from those of patients without schizophrenia and healthy controls. In an attempt to determine whether exploratory eye movements provide valid markers for schizophrenia, the present collaborative study was conducted in six countries to analyze the stability of and variation in the following parameters of exploratory eye movements: the number of eye fixations (NEFs) and mean eye scanning length (MESL) in a retention task; the cognitive search score (CSS) that indicates how frequently the eye focused on each important area of a figure in order to recognize it in a comparison task; and the responsive search score (RSS), which reflects the frequency of eye fixations on each section of a figure in response to questioning in a comparison task. In addition, we investigated the validity of the currently employed discriminant function to extract a common feature of schizophrenia by applying it to the findings of the present study. The exploratory eye movements of 145 patients with schizophrenia, 116 depressed patients and 124 healthy controls at seven WHO collaborative centers in six countries were measured using eye mark recorders during viewing of stationary S-shaped figures in two sequential tasks. The RSSs of patients with schizophrenia were found to be significantly lower than those of depressed patients or healthy controls irrespective of geographical location, with no significant difference existing between the RSSs for depressed patients and those for healthy controls. By inserting the RSS and NEF data for each subject into the formula used to calculate discriminant function, patients with schizophrenia could be discriminated from depressed patients and healthy controls with a sensitivity of 89.0% and a specificity of 86.7%. The RSS is an exploratory eye movement parameter that detected schizophrenia irrespective of culture, race and various other subject variables. Furthermore, it is indicative of the stable, significant difference that exists between subjects with and without schizophrenia. The results of discriminant analysis confirm the previously reported validity of discriminant function.

Adult↗
PubMed2001

[Pulmonary edema caused by laryngospasm].

The authors report on a case of non-cardiac pulmonary oedema that developed in a young athletic man at an operating theatre. This unusual condition resulted from a laryngospasm followed by strenuous ventilation retractions. Diagnostic routine, differential diagnosis and treatment are described.

Adult↗
PubMed2001

A randomized, double-blind clinical trial using fixed daily doses of 100 or 200 IU of recombinant FSH in ICSI cycles.

The effect of 100 and 200 IU per day recombinant FSH (rFSH) on numbers of oocytes retrieved and the total dose used in ovarian stimulation before intracytoplasmic sperm injection was investigated in a double-blind, randomized multicentre trial. A total of 91 women was treated with a low-dose protocol and 88 with a high-dose regimen at five centres. For each started cycle, significantly more oocytes were retrieved in the 200 IU group than in 100 IU group (12.0 versus 5.7, P < 0.001); total rFSH consumption was 1121 and 1875 IU in the low- and high-dose groups respectively. Significant variations were noted between centres with regard to numbers of oocytes collected per started cycle, ranging from 2.8 to 7.2 in the 100 IU group and from 9.0 to 19.1 in the high-dose group. Exploratory analyses of secondary outcomes suggested there were no differences in vital pregnancy rates per started cycle (19.2 versus 16.9%) and per embryo transfer (26.2 versus 19.3%) in the low- and high dose groups respectively. There were four hospitalizations due to ovarian hyperstimulation syndrome, all in the 200 IU group.

Adult↗
PubMed2000

Insulin-like growth factor I in the anterior pituitary of the clawed frog Xenopus laevis: immunocytochemical and autoradiographic indication for a paracrine action and corelease with prolactin.

Insulin-like growth factor I (IGF-I) and its receptor are present in human and rat anterior pituitary. However, few data exist on the potential presence of IGF-I or its receptor in the non-mammalian pituitary and the cellular sites of IGF-I production have not been identified in any species. Thus, we investigated the anterior pituitary of the clawed frog Xenopus laevis which is widely used to study growth and differentiation. The study was performed with antisera against mammalian insulin-like growth factor I (IGF-I), prolactin (PRL) and growth hormone (GH) using immunohistochemical and immunocytochemical techniques. IGF-I binding was determined by in-vitro receptor autoradiography. The PRL-and GH-immunoreactive cells exhibited distinct distribution patterns. Neither at the light nor the electron microscopical level any colocalization of PRL-and GH-immunoreactivities was apparent. The PRL-immunoreactive cells exhibited round granules of medium electron density (mean diameter: 312 nm) and the GH-immunoreactive cells spherical granules of medium electron density (mean diameter: 165 nm). By the use of serial semithin sections IGF-I-immunoreactivity was exclusively located in PRL-immunoreactive cells. At the ultrastructural level, IGF-I-immunoreactivity was confined to the secretory granules in coexistence with PRL-immunoreactivity using the double labelling immunogold technique. Specific IGF-I binding sites were localized throughout the pituitary. The results provide evidence for a concomitant release of PRL and IGF-I and suggest autocrine/paracrine actions of IGF-I in the anterior pituitary.

Animals↗
PubMed1999

Immunohistochemical evidence for the presence, localization and partial coexistence of insulin, insulin-like growth factor I and relaxin in the protochordate Ciona intestinalis.

The occurrence and coexistence of peptides of the insulin-like growth factor (IGF)/insulin superfamily were investigated in the ovary and gastro-intestinal tract of the protochordate Ciona intestinalis. Antisera specific for mammalian IGF-I, insulin and relaxin were used in a double-immunofluorescence method on paraffin sections and with an immunogold technique on consecutive semi-thin sections. IGF-I and relaxin immunoreactions but no insulin immunoreactions occurred in the ovary and were confined to medium-sized and mature follicle cells. Two subpopulations of reacting follicular cells were present: those containing only IGF-I immunoreactivity (5%) and those containing IGF-I and relaxin immunoreactivities (95%). In the gastro-intestinal tract, IGF-I and insulin immunoreactions coexisted, whereas no relaxin immunoreactions were obtained. Gel chromatography and radioimmunoassay in Ciona ovary revealed IGF-I immunoreactivity in two peaks with apparent molecular masses of approximately 16 kDa and 3 kDa. The present results indicate that (1) the same IGF-I-related peptide probably occurs in gastro-intestinal tract and ovary, (2) three different members of the insulin/IGF family of peptides are probably present in protochordates, (3) different types of coexistence of these peptides seem to exist in protochordates, i.e. an IGF-I-related peptide and an insulin-related peptide in the digestive tract and, as shown previously, in central nervous system, and the IGF-I-related peptide and relaxin in the ovary, (4) an IGF-I-related peptide and relaxin may be involved in oocyte maturation in the protochordate ovary.

Animals↗
PubMed1998

[Thromboelastography--an instrument for the researcher or clinician?].

Thromboelastography is a method which is used experimentally since 1948. Since the end of the eighties it is experiencing a certain revival also in clinical medicine. The submitted case-record presents this technique as a very useful aid in the differential diagnosis of postoperative haemorrhagic conditions in cardiosurgery. Its application can facilitate aimed treatment of some typical disorders of haemocoagulation.

Aged↗
PubMed1998

Uroguanylin: gene structure, expression, processing as a peptide hormone, and co-storage with somatostatin in gastrointestinal D-cells.

Guanylin/GCAP-I and uroguanylin/GCAP-II are two structurally related peptides which play an important role in the regulation of water/electrolyte balance within the gut. In order to enable the investigation and comparison of both peptide hormones at the genomic level, we decided to clone the corresponding genes. The human gene for guanylin/GCAP-I and its 5'-flanking region have been described recently. Here, we report the three exon/two intron structure of the human uroguanylin/GCAP-II gene and its localization on chromosome 1 p35-34, as determined by radiation hybrid mapping. Together with data obtained for the guanylin/GCAP-I gene we show that these genes are localized in the same chromosomal area with other guanlyl cyclase-activating peptides like ANP etc. Northern hybridization revealed that the expression of the uroguanylin/GCAP-II gene is highest in the intestinal mucosa, especially in the ileum and colon. By means of polymerase chain reaction (PCR), an expression was also observed in the stomach where no guanylin/GCAP-I expression is detectable. Using immunohistochemical methods, uroguanylin/GCAP-II immunoreactive material was distinctly localized in D-type gastric and intestinal endocrine cells. Although the comparable data on the genomic organisation of both peptide hormones verify their high degree of relationship, this finding indicates a special task of uroguanylin/GCAP-II within the stomach, such as regulatory functions in gastric secretion. The redundant expression of the GCAP/GC-C system in the small and large intestine, however, is as yet unclear.

Amino Acid Sequence↗
PubMed1998

The early phase of glucose-stimulated insulin secretion requires nitric oxide.

Nitric oxide (nitrogen monoxide, NO) acts as a signal transducer in a variety of cells. In the present study rat pancreatic islets were perifused with physiologically relevant glucose concentrations in the presence or absence of various NO-modulating agents. Perifusion in the presence of 0.1-1 mmol/l of the NO synthase inhibitor, NG-monomethyl-L-arginine or of 10 micromol/l of the NO-scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), resulted in an inhibition of the early phase of glucose-stimulated insulin secretion by 60-65% and 46%, respectively. Light- and electron-microscopic studies revealed that pancreatic islets constitutively express NO-synthase in alpha and delta cells, where it is confined to the secretory granules. Therefore, these data indicate that NO may be important in the signal transduction pathway of the early phase of glucose-stimulated insulin secretion.

Animals↗
PubMed1998

Insulin treatment reduces the increased serum and lung angiotensin converting enzyme activity in streptozotocin-induced diabetic rats.

Serum and lung angiotensin-converting enzyme (ACE) activity is increased in the streptozotocin (STZ)-diabetic rat. In the present study, the effect of insulin treatment on this increased ACE activity in the STZ-diabetic rat was investigated. Serum and tissue ACE activity was determined by radiometric assay using [3H]-Hippuryl-glycyl-glycine as substrate. Fifteen days after onset of diabetes (n = 16), 8 rats received insulin daily (6-12 units/kg, s.c.) for 33 days, 8 diabetes rats remained untreated. Control, non-diabetic, rats (n = 8) received saline. The baseline serum ACE activity in the control group was 595 +/- 13 nmol/ml/min and did not change significantly throughout the study. However, serum ACE activity in the untreated diabetic rats increased significantly as of day 14 post-STZ (650 +/- 24 nmol/ml/min, p < 0.001) compared to the corresponding values of the control group and compared to baseline values. Insulin administration to diabetic rats starting on day 15 post-STZ caused a gradual reduction in serum ACE activity to basal values, being (527 +/- 22 nmol/ml/min) at day 47. ACE activity in lungs of untreated diabetic rats was increased by 46%, 47 days post-STZ. Insulin treatment reduced lung ACE activity to values similar to those observed in non-diabetic rats. These changes were associated with reduced kidney weight and urine volume. In summary, insulin administration to hyperglycaemic rats resulted in a reduction in the enhanced serum and lung ACE activity to values seen in non-diabetic rats. Normalizing the activity of the renin-angiotensin system may slow or prevent the glomerular hypertension, a major factor in the development of diabetic nephropathy.

Animals↗
PubMed1996

Localization, expression, and characterization of guanylin in the rat adrenal medulla.

The peptide guanylin, recently isolated from the intestine, and localized to cells of the gut mucosa, is involved in electrolyte/water transport in the intestinal epithelium by means of a paracrine mode of regulation. Since high amounts of this peptide are present also in the systemic circulation, we investigated the adrenal gland as a potential endocrine source of guanylin. Using a reverse transcriptase-polymerase chain reaction and hybridization with an internal oligonucleotide designed for rat guanylin, 514-bp signals were obtained in intestinal tissue and adrenal gland. Successive analyses of extracts from intestine and adrenal gland by HPLC, western blotting, and radioimmunoassay revealed the presence of the same high-molecular mass (about 12.4 kDa) guanylin that corresponds to the mass of the guanylin prohormone. About 60 fmol/ml of circulating immunoreactive guanylin was determined in plasma. Localization studies with antisera directed against different epitopes of guanylin revealed that, in the adrenal gland, guanylin immunoreactivity is restricted to the medulla, where it is mainly confined to norepinephrine chromogranin A-containing cells. On the ultrastructural level, guanylin immunoreactivity was exclusively located to secretory granules of chromaffin cells. The present data indicate that, in addition to entero-endocrine cells, the adrenal medulla represents a further source of guanylin. Thus, an endocrine mode of function of guanylin may accrue to its hitherto evidenced paracrine action in fluid transport in the intestinal epithelium. Furthermore guanylin may be considered as a neurohormonal peptide.

Adrenal Medulla↗
PubMed1993

[The differential diagnosis of Parkinson diseases--123I-IBZM-SPECT vs. the apomorphine test].

The aim of our study was to compare the striatal dopamine D2-receptor density as measured by 123I-IBZM-SPECT with the results of the apomorphine-test. 30 patients were studied; 21 with idiopathic Parkinson's disease (IPD), 9 with Parkinson plus syndromes (PPS). Patients with IPD showed a significantly higher striatal IBZM binding as compared to patients with PPS (p = 0.006). A good correlation between IBZM binding and outcome of the apomorphine-test was found (p = 0.006). Low striatal IBZM binding indicates reduced dopamine D2-receptor density. This compromises successful dopaminergic medical therapy and is indicative of non-IPD disease. 123I-IBZM-SPECT could be diagnostic aid in the work-up of patients with extrapyramidal movement disorders. The response to dopaminergic drug treatment might be precluded by IBZM-SPECT in patients with Parkinsonian syndromes.

Adult↗
PubMed1993

Dynamics of the effects of levoprotiline and maprotiline on EEG in patients with major depressive episodes (DSM-III-R).

The presented study compares the effect of the well-tested antidepressant maprotiline and a new antidepressant with an atypical pharmacological profile, levoprotiline, on EEG during repeated assessment after single dose administration. From the original number of 34 patients fulfilling the criteria of a major depressive episode (DSM-III-R) on account of a low-voltage record or pathological findings 11 were eliminated. To 12 of the remaining patients levoprotiline was administered and to 11 maprotiline, after a one-week placebo period, in doses of 150 mg. The EEG was recorded after an accommodation session immediately before, 1.5, 3, 4.5, 6 and 24 hours after a single dose administration. The record was taken on a 16-channel average reference montage at rest with closed eyes. Two-minute intervals were divided into 30 four-second periods at a sampling frequency of 128 Hz. From the signal by means of FFT the spectra were estimated and the mean spectrum for the entire recording was calculated. This was then divided into 10 frequency bands. The new method of frequency analysis of alpha-entropy was also used which is a global measure of the difference between two spectra. Three hours after administration of a single dose levoprotiline had an EEG profile corresponding to the profile of tricyclic antidepressants, i.e. it increased the values of the power spectra density in the region of 5-8.5 Hz and in the entire beta band; the decline of power in the alpha band was, however, absent. As regards maprotiline, 3 hours after administration a profile typical for antidepressants was not found; obviously because of the great variance of values of power spectra density as a result of great interindividual differences in the ingestion phase. Changes of the EEG spectrum expressed as values of alpha-entropy during different periods of apparently assessment are not incidental. After the initial rise of values a decline occurs.

Adult↗
PubMed1992

[Results of a clinical trial of levoprotiline].

The authors submit results of a double blind clinical trial of levoprotiline controlled by maprotiline. In the multicentre study (which is processed and interpreted in stages) participated after written informed consent 58 patients with the diagnosis of a major depressive disorder. During the first three weeks the results of levoprotiline and maprotiline (from 26 patients each) were processed. The trial lasted 42 days. The psychopathology of the patients was evaluated by independent blind raters by means of Montgomery and Asberg's scale (MADRS), Hamilton's scale for depression (HRDS) and general clinical impression (CGI). In all patients also the pharmacological and EEG response was assessed. In comparison to maprotiline, levoprotiline was clinically ineffective. Its plasma levels (40 ng/ml) were one third to one half of the values obtained with maprotiline in the same daily dosage (150 mg). Although levoprotiline has an EEG profile typical for classical thymoleptics, its clinical antidepressive action is negligible.

Adult↗