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Biomedical subjects

W Hanke

Publications and source records attributed to W Hanke.

At least 37 records · Page 2Linked to original sources
PubMed2000

The ageing of the low-frequency water disturbances caused by swimming goldfish and its possible relevance to prey detection.

Wakes caused by swimming goldfish (Carassius auratus) were measured with a particle image velocimetry system and analyzed using a cross-correlation technique. Particle velocities in a horizontal plane (size of measuring plane 24 cmx32 cm or 20 cmx27 cm) were determined, and the vorticity in the plane was derived from these data. The wake behind a swimming goldfish can show a clear vortex structure for at least 30 s. Particle velocities significantly higher than background noise could still be detected 3 min after a fish (body length 10 cm) had passed through the measuring plane. Within this time span, the lateral spread of fish-generated wakes could exceed 30 cm for a 10 cm fish and 20 cm for a 6 cm fish. Measurements in a man-made open-air pond showed that water velocities in a quasi-natural still water environment can be as small as 1 mm s(-)(1). Background velocities did not exceed 3 mm s(-)(1) as long as no moving animal was present in the measuring plane. The possible advantage for piscivorous predators of being able to detect and analyze fish-generated wakes is discussed.

Aging↗
PubMed2000

[Reproduction disorders in women occupationally exposed to pesticides].

Among many harmful factors typical of occupations in agriculture, pesticides occupy a specific place. The effects of such a hazard may be manifested among others by reproduction disorders. In the epidemiological studies, presented in this paper, the analysis was focused more on the relationship between employment in agriculture and the incidence of congenital malformations, miscarriages, low birth weight, small-for-gestational-age, preterm delivery and still births, and less on conditions of exposure to various chemical compounds in greenhouses. The results of the analyses indicate that employment in agriculture increases the risk of congenital malformations to infant, particularly such as orofacial cleft, birthmarks in the form of haemangioma, as well as musculoskeletal and nervous system defects. The data on the effect of employment in agriculture on low birth weight are unequivocal. The study did not reveal significantly increased risk of small-for-gestational-age birth, but it was found that exposure to pesticides may contribute to still births. The results presented show significant risk of reproduction disorders in women employed during pregnancy in conditions of pesticide exposure. They also justify the placement of pesticides among factors the pregnant women should not be exposed to, at least until employers in Poland are able to assess individual risk of women employed under exposure to pesticides.

Abortion, Spontaneous↗
PubMed2000

[Influence of environmental smoke exposure during pregnancy on umbilical blood flow velocity].

Influence of environmental smoke exposure during pregnancy on umbilical blood flow velocity and newborns birthweight was assessed in prospective study among 116 pregnant women between 20 and 24 week of pregnancy. The main aim was to search for a possible correlation between cotinine, an effective marker of smoke exposure, and umbilical blood flow as measured by S/D, RI and PI ratios. This study shows a significant increase of systolic/diastolic velocity ratio of the umbilical artery according with increased cotinine levels, either for active or passive smokers. Increase of S/D ratio > 3.0 in umbilical artery in 20-24 week of pregnancy was negatively correlated with newborns birthweight. The results of this study suggest that active and passive smoking by pregnant women causes a direct increase in the vascular resistance of the placenta and contribute to the decreased of the newborns birthweight associated with smoking.

Birth Weight↗
PubMed2000

[The effect of environmental tobacco smoke on birthweight: a prospective study employing biomarkers of exposure].

The main goal of the project was to estimate the effect of environmental tobacco smoke (ETS) exposure on the birthweight. In a cohort of 196 pregnant women in 20-24 week of pregnancy the serum and urine cotinine levels were determined. The cohort included randomly selected pregnant patients of a maternity units in Lodz, Poland. To assess a 24 h exposure to ETS preceding the day of examination, both serum and urine cotinine measurements were applied. A statistically significant relationship was found between serum cotinine concentration and brithweight. The newborns of nonsmoking mothers whose serum cotinine levels were characteristic for passive smoking (2-25 ng/ml) had their birthweight lower by an average of 30 g, compared to those of women who were not exposed to ETS (serum cotinine below 2 ng/ml). It was concluded that more effective public health measures should be undertaken to ensure a tobacco smoke-free environment for pregnant women. Until this goal is achieved, pregnant women should be informed about health risks from ETS exposure so that they would avoid it both at home and workplace.

Adult↗
PubMed2000

[Efficacy of vaccination against influenza among working people--results of epidemiological studies].

Influenza among working people is responsible for the enhanced sickness absenteeism, limited work capacity and efficiency, as well as for the increased health service demand. The efficacy of vaccination against influenza has been assessed most frequently on the basis of clinical symptoms without taking virological tests to confirm the presence of virus in the patients' serum. According to current epidemiological studies on the occurrence of the influenza-like symptoms, the efficacy of vaccination usually range between 18.3-23%. However, values reaching 54% or even 88% have also been noted. Only a few single studies did not show significant effects of vaccination against influenza. Savings due to vaccination have ranged from several to 20, and in one study even to 46 dollars per one vaccinated worker. These economic differences should be mainly attributed to the differences in the structure of direct and indirect costs taken into account. The direct costs depend, to a great extent, on whether savings due to the number of visits not attended by patients who had been vaccinated and thus, not suffered from flue, as well as the costs incurred in vaccination-promoting programmes and their implementation by nurses have been taken into account. In the structure of indirect costs, the largest difference was noted in regard to savings due to not wasted working time. These savings ranged from 9.9 dollars per one worker in Poland to 52.87 dollars in Canada. The range of savings obtained depends on the index of workers' participation in the vaccination programme, and this index is usually a derivative of the input of resources into the promotion of such kind of health conducive behaviour. It seems that in view of preliminary positive results of the economic assessment, the employers will encourage their workers to undergo preventive vaccination against influenza. It may be expected that appropriate promotion actions of much wider scope will be undertaken that will contribute to the increased number of vaccinated workers. However, the final decision in this respect will always depend on the worker's good will.

Canada↗
PubMed1999

Lubeluzole shows neuroprotective effects in an "in-vitro"-model for neuronal lesions in the chicken retina.

In this study, the isolated chicken retina was used as an "in-vitro"-model for investigation of neuronal lesions to show the neuroprotective effects of lubeluzole. Lubeluzole is a neuroprotective compound that has been shown to stereoselectively rescue sensorimotor function and reduce infarct size in photochemical stroke models in rats. In the retina, the typical cell swelling of a developing lesion is accompanied by a very strong intrinsic optical signal (IOS), occurring simultaneous with the electrical signal which is based on changes in light scattering. In the presented model, lesions were elicited electrically with a tungsten microelectrode (0.1 MOmega). The degree of damage was evaluated with optical methods by measuring area and brightness of the affected tissue. Lubeluzole was much more effective in reducing the growth of the lesions than its R-isomer. However, both compounds enhanced the possibility of the neuronal tissue to recover after excitotoxic stimuli.

Animals↗
PubMed1999

Biphasic effects of melatonin on the propagation of excitation waves in the chicken retina.

The retinal spreading depression (SD) is a propagating wave in an excitable medium, the neuronal tissue of the retina. Its velocity is about 3 mm/min and it is accompanied by a variety of changes in the tissue, including electrical and optical events. The pronounced intrinsic optical signal (IOS) of the retinal SD makes it an extremely versatile tool for the investigation of the action of drugs on neuronal tissue and more specific on propagating excitation waves in neuronal tissue. Furthermore, in the last decade increasing evidence has been collected, which shows that SD waves are the basic mechanism of the aura in classical migraine. We have investigated the influence of melatonin on the propagation of retinal SD waves as it has been postulated to have protective effects on neuronal tissue. The results demonstrate that melatonin indeed slows down the retinal SD, however, only in a defined concentration range. Additionally, it changes the IOS of the wave.

Animals↗
PubMed1999

Latex allergy in Polish nurses.

BACKGROUND: Reports on the studies conducted in Western Europe and North America revealed that from 2.8 to 16.9% of the health care personnel were allergic to latex. No respective data are available from Eastern European countries. METHODS: A postal questionnaire inquiring about the history of latex-induced allergic reactions was distributed among 3,750 nurses. The participation rate was 77.3%. To verify the results of the survey, in randomly selected nurses, skin prick tests with latex and tropical fruit allergens, evaluation of total IgE, and specific anti-latex IgE, skin and nasal provocation with latex were performed. RESULTS: Allergic symptoms in the workplace were reported by 1,016 subjects (35%); out of this group 847 (29.2%) persons associated the symptoms with latex exposure. The group of cases with self-reported latex allergy revealed a significantly increased frequency of history of atopy, allergy to beta-lactam antibiotics and tropical fruits. Allergy to latex was confirmed in 33.3% of randomly selected nurses with a positive history of occupational allergy. It was found that 18.6% of nurses working at hospital wards were allergic to latex. The 95% CI was estimated to be 13.5-23.6%. CONCLUSIONS: Latex allergy is an important health problem among nurses in Poland. Atopy, allergy to beta-lactam antibiotics and tropical fruits, are the risk factors for latex allergy.

Adult↗
PubMed1999

Heavy physical work during pregnancy--a risk factor for small-for-gestational-age babies in Poland.

BACKGROUND: Heavy physical work is still considered one of the most prevalent risk factors of negative pregnancy outcome. The present study was undertaken to evaluate the impact of heavy physical work during pregnancy, based on subjective assessment of workload, on the risk of delivering a small-for-gestational-age (SGA) baby. METHODS: Job characteristics were compiled for 1,064 working women from the Lódź region (8% population sample) based on questionnaire responses. Energy expenditure during daily work was estimated. SGA was diagnosed when the birth weight was below the 10th percentile of the standard curves for central Poland. The SGA group comprised 78 women who delivered SGA babies, while the non-SGA group consisted of 986 women with eutrophic newborns. RESULTS: An excessive risk of SGA was found in the group reporting heavy physical effort at work. The physical effort perceived as heavy by pregnant women appeared to be a better predictor of SGA manifestation than the estimated energy expenditure at work. CONCLUSIONS: The information obtained from a pregnant worker should constitute an essential decisive factor for determining the time of work cessation during pregnancy.

Adolescent↗
PubMed1999

Identification of a cyclic nucleotide- and voltage-activated ion channel from insect antennae.

From an antennal cDNA library of Heliothis virescens a clone has been isolated encoding a polypeptide of 678 amino acids. Data base comparisons and primary structure analysis of the deduced protein sequence (HvCNG) indicated significant homology to cyclic nucleotide and voltage-activated ion channels including six putative membrane spanning domains, a putative cyclic nucleotide binding site, a pore region and a voltage-sensor motif. Heterologous expression of the cloned cDNA in Sf9 cells resulted in a polypeptide of the predicted molecular mass. Patch clamp analysis allowed to record the activity of the identified HvCNG channels; they were activated by cAMP but also by hyperpolarization. The channel displayed in potassium solution a conductance of 30 pS; the ion selectivity was calculated as PK/PNa approximately 3. Northern blot analysis revealed that the channel is highly expressed in the antennae; weaker signal were detected in heads and legs. In situ hybridization of tissue sections through the antennae showed a spatial distribution of reactive cells; they are located beneath sensillar hairs. Thus, a novel channel type has been identified which may play an important role in antennal cells.

Amino Acid Sequence↗
PubMed1999

The puzzle of hydrodynamic information processing: how are complex water motions analyzed by the lateral line?

We studied the discharges of neurons in the ascending lateral line pathway in response to the complex water motions generated by a moving object. The wave stimulus generated by the object was monitored with a hot-wire anemometer and with a custom-built particle imaging system. Responses of central lateral line neurons differ from those of primary afferent fibers in aspects like temporal discharge patterns and directional sensitivity. The data are consistent with the hypothesis that central lateral line neurons integrate input from many afferents innervating neuromasts distributed across large portions of the body surface.

Animals↗
PubMed1999

Functional alpha6-containing nicotinic receptors are present in chick retina.

Despite the fact that the neuronal chick alpha6 subunit was first cloned several years ago and recently has been shown to form acetylcholine (ACh)-activated channels in heterologous systems, no information is yet available concerning the structure and function of the alpha6-containing nicotinic receptors in neuronal tissues. Using subunit-specific antibodies directed against two different epitopes of the chick alpha6 subunit, we performed immunoprecipitation experiments on immunopurified alpha6-containing receptors radiolabeled with the nicotinic agonist [3H]epibatidine (Epi): almost all of the alpha6 receptors contained the beta4 subunit, 51% the beta3 subunit, 42% the alpha3 subunit, and 7.5% the beta2 subunit. Western blot analyses of the purified receptors confirmed the presence of the alpha3, beta3, beta2, and beta4 subunits, and the absence of the alpha4, alpha5, and alpha7 subunits. The alpha6-containing receptors bind [3H]Epi (Kd = 35 pM) and a number of other nicotinic agonists with very high affinity, the rank order being Epi >> cytisine > nicotine > 1, 1-dimethyl-4-phenylpiperazinium > acetylcholine > carbamylcholine. The alpha6 receptors also have a distinct antagonist pharmacological profile with a rank order of potency of alpha-conotoxin MII > methyllycaconitine > dihydro-beta-erythroydine > MG624 > d-tubocurarine > decamethonium > hexamethonium. When reconstituted in lipid bilayers, the alpha6-containing receptors form functional cationic channels with a main conductance state of 48 pS. These channels are activated by nicotinic agonists in a dose-dependent manner, and blocked by the nicotinic antagonist d-tubocurarine.

Amino Acid Sequence↗
PubMed1999

Passive smoking and pregnancy outcome in central Poland.

1. The present investigation was undertaken to evaluate the effect of environmental tobacco smoke (ETS) on the risk of preterm delivery (PD) and small-for-gestational age (SGA) infants in a female non-smoking population of central Poland. 2. The study group were 1751 women classified as non-smokers in the comprehensive project on 'Socio-economic and environmental risk factors of preterm delivery and small-for-gestationaI-age babies in central Poland' conducted on a randomly selected population of 2080 women who gave birth to a child between June 1, 1996 and May 31, 1997. The PD group comprised 95 non-smoking women who delivered before 37 weeks of pregnancy and the SGA group included 111 non-smoking mothers of babies with birthweight below the 10th percentile of the standard curves for central Poland. Passive exposure to tobacco smoke was determined based on a structured interview. 3. In the stepwise multiple logistic regression model maternal passive smoke exposure lasting 7 h or more was found to be a significant risk factor for preterm delivery. No significant effect of passive smoking on the risk of SGA was observed. 4. The information about the adverse effects of ETS exposure on pregnancy duration and outcome should be incorporated in the health promotion programmes for women.

Female↗
PubMed1999

[Evaluation of the effectiveness of a low-dose aspirin in the treatment of intrauterine growth retardation (IUGR)].

OBJECTIVE: To evaluate the benefits of IUGR treatment by low doses of acetylsalicylic acid (ASA) (1.5 mg/kg) compared to the standard method. The study was based on the reports that aspirin at low doses shifts prostacyclin/tromboxan A2 balance to the dominance of prostacyclin by inhibiting cyclooxygenase activity in platelets, which results in the improvement of the utero-placental circulation. MATERIAL AND METHOD: 31 pregnant women with diagnosed fetal IUGR were randomly assigned to two groups, receiving either low-dose ASA (n = 22) or the standard treatment (Sadamin, Partusisten, glucose i.v., amino acids i.v.) for 10 days. Ultrasound examination of the biometric parameters of the fetus (BPD, AC, FL) was performed and estimated fetal weight (EFW) calculated before and after treatment. The birthweight of infants in the two examined groups was compared. RESULTS: The mean increase in EFW was higher in the aspirin-treated group compared to that receiving standard treatment (478 g vs 246 g, p < 0.05). In all the biometric parameters under study a higher increase was noted in the group with aspirin treatment; however, the difference was not statistically significant. The mean birthweight was found to be higher in the ASA group as well (2856 g vs 2511 g). The frequency of small-for-gestational-age (SGA) infants (birth weight below 10th percentile) was lower in the ASA group than in the controls (27% vs 55%). The low-dose aspirin therapy did not produce any adverse side-effects either among mothers of infants. CONCLUSION: The treatment with low doses of aspirin reduces the proportion of SGA babies and increases birthweight in the case of a diagnosed fetal growth retardation. Since the number of subjects in this study was relatively small, further clinical trials are necessary to evaluate the effectiveness of IUGR treatment by low-dose aspirin.

Adult↗
PubMed1999

[Unemployment during pregnancy: direct or indirect risk factor of prematurity and fetus hypotrophy?].

The question as to whether in a transitional phase in the political and socio-economic development in Poland, an increased threat of unemployment may also produce health effects manifested by an elevated risk for prematurity and fetus hypotrophy is one of important challenges. If the answer is positive then this issue should have much stronger impact on political and economic decisions. The data obtained from numerous studies carried out in countries of western Europe and the United States shows that the job performance during pregnancy under conditions free from occupational exposure and arduousness does not directly augment the risk of detrimental effect to the health of pregnant woman or her fetus. Just on the contrary, it was found that job performance during pregnancy, and strictly speaking steady employment during this period may somewhat become a 'protective factor'. In Poland, the highest rate of unemployment is observed among women in the 18-24 age group, that is at the age most suitable for procreation. Nowadays it is common that the decision on child-bearing is postponed until the economic status of the woman or her family comes to be more stable. On the other hand, in the population of women looking for a job but determined to set up a family prematurity is quite common that results only in part from an excessive effect of risk factors for this pathology very typical of this social group, like smoking, single parenthood, early or late child-bearing age. After adjusting these factors, the risk of prematurity decreased considerably but it was still high. It is thought that stress and the sense of threat and uncertainty is mostly responsible for this phenomenon. An increased risk of fetus hypotrophy among unemployed women after considering all confounding factors, was not observed.

Adolescent↗
PubMed1998

An immunohistochemical and morphometric analysis of insulin, insulin-like growth factor I, glucagon, somatostatin, and PP in the development of the gastro-entero-pancreatic system of Xenopus laevis.

The ontogeny of the classical islet hormones insulin (INS), glucagon (GLUC), somatostatin (SOM), and pancreatic polypeptide (PP) as well as insulin-like growth factor I (IGF-I) in the gastro-entero-pancreatic (GEP) system of Xenopus laevis (stages 41-66) was studied using double immunofluorescence and morphometric analysis. As early as stage 41, clustered INS-immunoreactive (-IR) and isolated GLUC-IR cells occurred in the pancreas. The first SOM-IR cells appeared at stage 43, followed by PP-IR cells at stage 46. About 79% of the PP immunoreactivity was confined to a subpopulation of the GLUC-IR cells. Both the GLUC/PP-IR cells and the PP-IR cells were located in a distinct area of the pancreas. The first islets occurred in premetamorphosis (around stage 50) and comprised mainly INS-IR and GLUC-IR cells. The majority of SOM-IR, PP-IR, and GLUC/PP-IR cells was dispersed. The numbers of hormone cells remained quite constant until the end of prometamorphosis (stage 58). Around stages 60-62, the islets were partly disintegrated and the numbers of islet cells slightly decreased. At stage 63, the cell number began to increase and reached the levels typical for the adult around stage 66. After metamorphic climax, the islets were reformed. In the gastrointestinal tract, transient INS-IR cells occurred prior to the adaptation of the gastrointestinal tract to feeding (stages 41-44) and during metamorphosis when there is remodeling of the gastrointestinal tract (stages 60-63). Therefore, INS released from the transient mucosal INS-IR cells may be involved in the temporary proliferation of mucosal epithelial cells. The first GLUC-IR and SOM-IR cells were seen at stage 41. PP-IR cells followed at stage 46. In contrast to the islets, GLUC-IR and PP-IR cells constituted different cell populations. Around stage 46, the first IGF-I immunoreactions appeared in the GEP-system. In pancreas, IGF-I immunoreactivity was found in the GLUC/PP-IR, cells (85-99%) but was absent from INS-IR, GLUC-IR, and SOM-IR cells. The IGF-I-IR gastro-entero-endocrine cells, however, seemed to contain none of the classical islet hormones.

Animals↗
PubMed1998

Pharmacological modulation of the refractory period of retinal spreading depression.

Spreading depression (SD) is a propagating wave of neuronal activity in the central nervous system and may play a role in triggering classical migraine. The retina serves as a model system for examining the phenomenon of SD and the influence of various drugs on it. After a SD wave passes a new wave can not be elicited in the absolute refractory period of the tissue (about 2 min), this is followed by a relative refractory phase of about 20 min before complete recovery. The aim of the present study was to describe the effects of Ba2+, a blocker of glial cell K+ channels, octanol, a gap junction blocker and diethylbarbiturate, a GABA(A) chloride channel-activating drug on the modulation of the refractory period of the retinal SD and to examine the possible mechanisms underlying this modulation. Two properties of SD, which are highly sensitive to any changes in the experimental conditions, are the propagation velocity of the wave and the accompanying slow negative potential shift. We measured the propagation velocity and the field potential amplitude in the chicken retina as a function of the recovery state of the tissue under control conditions and compared them with measurements in the presence of Ba2+, octanol or diethylbarbiturate. Under these conditions the manner of the recovery of the tissue changed significantly. Although after blocking the glial (Müller) cell K+ channels with Ba2+ (200 microM), the curve of recovery of the propagation velocity to its maximum value has the same shape as under control conditions, the propagation velocity is reduced in the whole recovery period and in the recovered retina to 84% of the control velocity. The importance of electrical coupling in the refractory phase and in the recovered tissue was examined by adding octanol (1 mM) to the perfusion solution. In this case the relative recovery phase was shortened and the field potential amplitude (110% of control) and propagation velocity (112% of control) are increased in the completely recovered retina. With the GABA(A)-chloride channel-activating drug diethylbarbiturate (800 microM) the propagation velocity (112% of control) and the amplitude of the field potential (111% of control) in the complete recovered retina are increased, but this seems to have no influence on the refractory state.

1-Octanol↗