Memes: Food for Attitudes and Behavior Crucial for Our Survival.

An effort is made to frame memes within a human evolutionary context in which memes are complex emotion-related tools of enhanced learning and spread of language, art, culture and technology. The basic idea is that any information can become a meme if emotions are evoked in a recipient. The evolution of human brain with memetic capabilities thus produced modern humans.

Are predictions of cancer response to targeted drugs, based on effects in unrelated tissues, the 'Black Swan' events?

Adverse effects of targeted drugs on normal tissues can predict the cancer response. Rash correlates with efficacy of erlotinib, cetuximab and gefitinib and onset of arterial hypertension with response to bevacizumab, sunitinib, axitinib and sorafenib, possible examples of 'Black Swan' events, unexpected scientific observations, as described by Karl Popper in 1935. The proposition is that our patients have individual intrinsic variants of cell growth control, important for tumor response and adverse effects on tumor-unrelated tissue.

Cystic fibrosis: model of pathogenesis based on the apical membrane potential.

A simple model of cystic fibrosis (CF) is proposed, based on the apical membrane (ApM) potential. The ApM of epithelial cells is highly permeable to sodium and activation of CFTRs makes it permeable to chloride. Calculated ApM potentials of cells with activated cystic fibrosis transmembrane conductance regulators (CFTRs) are between the sodium and chloride Nernst values and thus allow rapid absorption of both ions in exocrine glands.

Model of pulmonary fluid traffic homeostasis based on respiratory cycle pressure, bidirectional bronchiolo-pulmonar shunting and water evaporation.

The main puzzle of the pulmonary circulation is how the alveolar spaces remain dry over a wide range of pulmonary vascular pressures and blood flows. Although normal hydrostatic pressure in pulmonary capillaries is probably always below 10 mmHg, well bellow plasma colloid pressure of 25 mmHg, most textbooks state that some fluid filtration through capillary walls does occur, while the increased lymph drainage prevents alveolar fluid accumulation. The lack of a measurable pressure drop along pulmonary capillaries makes the classic description of Starling forces unsuitable to the low pressure, low resistance pulmonary circulation.

Intestinal gases and flatulence: possible causes of occurrence.

All gases entrapped in closed body cavities are destined to be partially or completely absorbed. Intestinal gases often accumulate and cause flatulence. This paper proposes a simple concept of intestinal gas occurrence based on our knowledge on gas resorption in other body cavities.

A model of dual circulation in liver acini with hypoxia regulated adenosine secretion.

It was postulated by W.W. Lautt that the hepatic artery flow compensation for changes in portal vein flow (the 'hepatic arterial buffer response') is regulated through the portal blood washout of adenosine from the small fluid compartment that surrounds the hepatic arterial resistance vessels.

Inertia of endocrine systems due to hormone binding to circulatory proteins.

It is often presumed that the main role of hormone binding to albumins and binding proteins (BPs) is to reduce oscillating levels of free hormone molecules and to transport steroid hormones. This paper is an attempt to define possible consequences of hormone molecules binding to carrier proteins in circulation. Binding to albumins and BPs prevents exact and quick control of hormone actions.

Model of interstitial pressure as a result of cyclical changes in the capillary wall fluid transport.

Reported interstitial pressures range from -8 to +6 mm Hg in different tissues and from <-20 mm Hg in burned tissue or more than +30 mm Hg in tumors. We have tried to link interstitial pressure to the here proposed cyclical changes in the fluid transport across the capillary wall. In the presented model interstitial pressure is considered as an average of pressures in numerous pericapillary spaces.

A model of the gastric gland ejection cycle: low ejection fractions require reduction of the glandular dead space.

This paper was inspired by the reported results of authors from Uppsala and Lund that gastric glands in rats rhythmically contract 3-7 cycles per minute and develop luminal pressures more than 10 mmHg. To ensure that pepsinogen is not retained in the acid-rich section of the gland, ejection fractions would need to be more than 50% of the gland volume. We have tried to calculate the ejection fraction of such contractions.

A model of hydraulic interactions in liver parenchyma as forces behind the intrahepatic bile flow.

The small diameters of bile canaliculi and interlobular bile ducts make it hard to attribute the bile flow solely to the process of secretion. In the model liver within its capsule is considered a limited space in which volume expansions of one part are possible only through the shrinking of other parts. The liver capsule allows only very slow volume changes.

Minoxidil and male-pattern alopecia: a potential role for a local regulator of sebum secretion with vasoconstrictive effects?

Regulation of the hair cycle takes place at the pilo-sebaceous unit with the sebaceous gland as a sex hormone-dependent part. Although minoxidil stimulates proliferation of follicular cells and activation of prostaglandin endoperoxide synthase-1, it was suggested that other mechanisms, such as an increase in the local blood flow, might mediate the drug effect on hair growth. If that is the case, it is possible that minoxidil counteracts some vasoconstrictive mediator of male-pattern alopecia.

Endothelin-secreting tumors and the idea of the pseudoectopic hormone secretion in tumors.

Ectopic hormone secretion in tumor cells is here described as an amplification of hormone production already present in normal, nonendocrine tumor-originated tissue. This idea is tested on the available data regarding endothelin-1 (ET-1) secreting tumors. The endothelins are ubiquitous regulatory peptides produced by various tissues.

Simulation model of defective insulin receptors as byproducts of receptor recycling.

Our simulation model assumes that the defective insulin-binding receptors in non-insulin-dependent diabetes (NIDDM) patients result from functional receptor recycling. The model is a short program written in MS DOS 5.0 Qbasic.

Computer simulation of factors involved in the down-regulation of hormonal effects.

Down-regulation of hormonal effects is in the presented simulation related to the number of functional receptors and quantity of available hormonal stimulation. The former is in the model substituted with the quantity of stimulation able to produce a full down-regulation (Hs100) of target cells. The halftime (t1/2) of the hormonal effect recovery means the interval before the second hormonal stimulation can elicit half of the initial hormonal effect.

Mechanisms of prion diseases described as long-lasting disorders of the blood-brain barrier system.

Prison diseases can be described as disorders wherein circulating prion molecules of external origin intervene with the normal synthesis of similar molecules in the central nervous system. The hypothesis is that the endogenous prion-like molecules denote the blood-brain barrier discontinuity. In the case of barrier discontinuity, small numbers of hypothetical signal molecules enter circulation and attach to the receptor sites in the neighbouring blood vessels.

The role of gastric mast cells, enterochromaffin-like cells and parietal cells in the regulation of acid secretion.

The idea presented here is that, in gastric mucosa, two independent regulatory systems use the same transmitter: histamine molecules. The IgE/mast cell system is dispersed throughout the body, while the other regulates the gastric acid secretion. IgE molecules in gastric mucosa are attached to the mast cells.