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Biomedical subjects

E Polak

Publications and source records attributed to E Polak.

12 recordsLinked to original sources
PubMed2001

Mitral annular calcifications and aortic plaques as predictors of increased cardiovascular mortality.

OBJECTIVES: Mitral annular calcifications (MAC) and aortic plaques are predictive for higher incidence of recurrent embolic events, the presence and severity of coronary artery disease and total cardiac deaths. However, no data exist comparing the impact of combined presence of both aortic plaques and MAC on embolic events, deaths associated with cerebral embolism or cardiac deaths during the follow-up. PATIENTS AND METHODS: In 100 consecutive patients with aortic plaques detected by transesophageal echocardiography (mean age 69.8 + 8.9 years, range 39-93 years, 49 males, 51 females) and in 49 age- and sex-matched control subjects (mean age 69.4 + 7.8 years, range 46-89 years, 27 males, 22 females) without aortic plaques (control group), the incidence of embolic events, deaths associated with embolic events and total cardiac deaths were evaluated during a mean follow-up of 32 +/- 9.7 months. The effect of the presence or absence of MAC on these parameters was also evaluated. RESULTS: Compared with the control group, patients with aortic plaques had a higher frequency of hypertension (p < 0.001), hypercholesterolemia (p < 0.01), smoking history (p < 0.01), MAC (p < 0.00001) and the presence of atherosclerotic changes in the carotid arteries (p < 0.05). During the follow-up, patients with aortic plaques had a higher incidence of stroke or transient ischemic attack (p < 0.0001), deaths associated with stroke (p < 0.005) and total cardiac deaths (p < 0.05) compared with the control group. Patients with both aortic plaques and presence of MAC had during the follow-up a significantly higher incidence of deaths associated with stroke (p < 0.0001, 16.0 times higher) and total cardiac deaths (p < 0.005, 4.7 times higher) compared with those without MAC and the presence of aortic plaques. Multivariant regression analysis showed MAC (p < 0.01) and hypercholesterolemia (p < 0.05) were the only independent predictors of stroke. MAC (p < 0.05) and age (p < 0.000001) were the only independent predictors of total cardiac death and stroke. Independent predictors of both aortic plaques and MAC were coronary artery disease (p < 0.00001), stroke (p < 0.005), hypertension (p < 0.001), female gender (p < 0.01) and hypercholesterolemia (p < 0.005). CONCLUSIONS: The findings of both aortic plaque and mitral annular calcification are highly predictive not only for strokes, but also for deaths associated with cerebral embolism and total cardiac deaths and are probably strong markers for higher severity of coronary artery disease. They are more predictive if both are present simultaneously compared to the presence of either MAC or aortic plaque alone.

Adult↗
PubMed1997

Asexual sporulation in coprinus cinereus: structure and development of oidiophores and oidia in an amut bmut homokaryon

Polak, E., Hermann, R., Kues, U., and Aebi, M. 1997. Asexual sporulation in Coprinus cinereus: Structure and development of oidiophores and oidia in an Amut Bmut homokaryon. 22, 112-126. Coprinus cinereus strain AmutBmut is a homokaryon with mutations in both mating type loci. It produces asexual spores (oidia) in sticky liquid droplets on specialized aerial structures (oidiophores). These oidiophores have uninucleate cells and are organized as those of the monokaryon 5026 from which the strain derived. However, unlike in the monokaryon, oidiophores in strain AmutBmut are induced by light. Young oidiophores are easily detected upon light induction and the process of oidiophore development is readily followed in this strain. Fully grown oidiophores consecutively give rise to short branches (oidial hyphae) that break up into two or occasionally three uninucleate oidia (arthroconidia) until up to 200 oidia are collected at the tip of the oidiophore. Mature spores are enclosed by a mucilage and a double-layered primary cell wall with hair-like structures except for the sides of former cell attachments. In a summary of our microscopic observations on developing oidiophores and nuclear stainings we present a model showing the successive steps of oidiophore and spore development.

Journal Article↗
PubMed1988

Altered pulsatile pattern of luteinizing hormone in men with idiopathic normogonadotropic oligospermia.

Gonadotropin serum levels and pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) are regulated by sexual steroids and perhaps inhibin, but the relative rates of LH and follicle-stimulating hormone (FSH) secretion are modulated by the frequency of GnRH pulses. This study evaluated LH pulsatility in patients with idiopathic normogonadotropic oligospermia (INO) and normal men before and after clomiphene citrate (CC) administration. INO patients evidenced a lower mean LH levels (P less than 0.001), a higher mean pulse frequency (P less than 0.05) and similar pulse amplitude than normal men. CC induced in normal men a higher LH and testosterone (T) increments and increased pulse amplitude only in normal men. Estradiol (E2) showed no difference in either group. Patients with INO might evidence a hypothalamic disorder that may alter pulsatile GnRH secretion. A different response to CC in patients with INO seems to lend support to a primary hypothalamic lesion. A probable gonadotropin imbalance might alter intratesticular concentrations of T and E2 and be the cause of spermatogenic failure.

Adult↗
PubMed1987

Intraoral periosteal nodular fasciitis.

Intraoral periosteal nodular fasciitis is an extremely rare tumor with only 2 cases having been previously recorded in the literature. We report here the 3rd case and review the characteristic features, the differential diagnosis and the treatment of intraoral periosteal nodular fasciitis.

Alveolar Process↗
PubMed1983

Chemical-modification studies on rat olfactory mucosa using a thiol-specific reagent and enzymatic iodination.

1. A rat olfactory preparation, suitable for biochemical studies in vitro on olfactory mechanisms, is described. 2. The effects of the impermeant chemical modification reagents mersalyl (a thiol reagent) and enzymatic iodination, on the amplitude of the electroolfactogram (EOG) responses elicited from rat olfactory mucosa by pulses of odorant vapours was studied using 12 odorants differing widely in odour quality and molecular structure: amyl acetate, carvone, decanal, butylamine, cineole, citronellol, cresol, diacetyl, dimethylethyl-pyrazine, naphthalene, octanethiol and valeric acid. 3. Both reagents irreversibly reduced the EOG amplitude to all odorants to an extent dependent on the reagent concentration. Two subpopulations of animal preparations could be distinguished on the basis of the extent to which they survived the iodination whereas mersalyl appeared to sample a single population of preparations. 4. Small but statistically significant differences were observed between the responses of each odorant with each reagent but no simple correlation between either the molecular structure or odour quality of the odorants and the reagent effect is apparent for the case of mersalyl. With iodination the responses from the three flexible-aliphatic-chain odorants were reduced to a greater extent than the other odorants, all of which had a dissimilar molecular structure. 5. The ability of three odorants, amyl acetate, carvone and decanal, to protect the receptors for the odorants against chemical modification was investigated. The protecting odorants were applied directly to the mucosa as a dilute solution in Ringer's medium. No specific odorant protection effects were observed. 6. The results are discussed in relation to a model of the olfactory mechanism involving relatively non-specific receptor proteins. Each receptor type is envisaged as interacting weakly with a number of odorants and each odorant interacts with a number of receptors.

Aldehydes↗
PubMedDate not supplied

Minimax optimization-based inverse treatment planning for interstitial thermal therapy.

The following work represents the development and evaluation of a minimax optimization-based inverse treatment planning approach for interstitial thermal therapy of cancer and benign disease. The goal is to determine a priori optimal applicator placements and power level settings to maintain the minimum tumour temperature, Tmin, and maximum normal tissue temperature, Tmax within a prescribed therapeutic temperature range. The temperature distribution is approximated by a finite element method (FEM) solution of a bioheat transfer equation on a nonuniform finite element mesh. Lower and upper therapeutic temperature thresholds are specified in the tumour and surrounding normal tissues. A constrained minimax optimization problem is formulated to determine optimal applicator positions and power level settings that minimize the maximum (rather than average) temperature errors in the target tumour region and surrounding normal tissues. The optimization problem is formulated for two general classes of interstitial heating applicators, those with and without a surface cooling mechanism. The viability and sensitivity of this approach is investigated in the two-dimensional setting for various tumour shapes and blood perfusion levels using surface-cooled and direct-coupled interstitial ultrasound applicator power deposition models. These preliminary results indicate the utility of this approach for meeting a prescribed Tmin/Tmax-based clinical objective criterion, and its potential for generating optimal treatment plans that can withstand variations or uncertainty in blood perfusion levels.

Energy Transfer↗