PubMed Health⌕ Search

Biomedical subjects

M Brust

Publications and source records attributed to M Brust.

13 recordsLinked to original sources
PubMed2002

Nanostructured cellular networks.

Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.

Cell Aggregation↗
PubMed1990

Magnesium dietary intake modulates blood lipid levels and atherogenesis.

In this study, we have examined the effects of variation in dietary Mg on the atherogenic process. Oral supplementation of rabbits fed a high cholesterol diet (1% or 2%) with the Mg salt magnesium aspartate hydrochloride (Magnesiocard) (i) lowers the level of serum cholesterol and triglycerides in normal (25-35%) as well as atherosclerotic (20-40%) animals and (ii) attenuates the atherosclerotic process markedly. In addition, we found that dietary deficiency of Mg augments atherogenesis markedly and stimulates (or activates) macrophages of the reticuloendothelial system. Evidence is presented to indicate that the hypercholesterolemic state may cause the loss of Mg from soft tissues to the serum, thereby masking an underlying Mg deficiency.

Animals↗
PubMed1990

Unusual observations on hypermagnesemic levels and cardiorespiratory effects in neonatal swine.

Mg is being used as a therapeutic agent in different clinical conditions, i.e. preeclampsia or eclampsia, and as a tocolytic agent to prevent premature delivery. For these reasons we decided to systematically investigate the cardiovascular and respiratory effects of excess Mg in 25 piglets less than 1 day to 3 months of age, lightly anesthetized with Saffan, tracheotomized, paralyzed with C-10 and artificially ventilated on 100% O2. A 1.0 M infusion of MgCl2 was given for 15-60 min, and arterial plasma samples were drawn before and at the end of the infusion for the determination of plasma Mg and Ca levels. Phrenic nerve activity was recorded monophasically simultaneously with arterial blood pressure, electrocardiogram, end-tidal CO2 and intratracheal pressure on a dynograph and on analog tape. In a subset of experiments (n = 6), spontaneous ventilation was monitored in piglets of different ages to determine the Mg concentration at which spontaneous ventilation ceased. Blood gases were measured at 45-min intervals, as well as both immediately before and after the MgCl2 infusion, and pCO2 and pH were maintained within normal limits. As a consequence of the high plasma concentration of Mg, mean arterial pressure and heart rate declined, and the inspiratory duration significantly decreased. Our results indicate that young piglets can survive high levels of plasma Mg (greater than 14 mM).

Animals↗
PubMed1990

Physicians' attitudes toward generic drug substitution by pharmacists.

Physicians in Southeast Texas were surveyed to obtain information on attitudes and practices concerning generic drug substitution. Questionnaires were sent to all practicing primary care physicians in the area, and responses were received from about 36% of them. The investigation revealed that a large percentage of physicians did not readily permit substitution. Two major reasons given for not permitting substitution were concerns about therapeutic inequivalency and doubts about pharmacists' ability to substitute safely.

Attitude of Health Personnel↗
PubMed1976

Fatigue and caffeine effects in fast-twitch and slow-twitch muscles of the mouse.

In excised, curarized and massively stimulated fast-twitch mouse gastrocnemius muscles the early twitch tension enhancements (treppe) during 1/s activity between 10 and 36 degrees C increase and affect more contractions as temperature increases. Tension output eventually declines at a temperature-independent rate. Half-relaxation time lengthens below 25 degrees C and shortens above 25 degrees C. During 1/0.63s twitches half-relaxation time lengthens even at 25 degrees C. In slow-twitch soleus muscles activity decreases twitch tension and half-relaxation time regardless of temperature. Activity shortens contraction times in both muscles. Oxygen lack induced by NaN3 cannot account satisfactorily for these results. Activation is apparently more plastic in the gastrocnemius than in the soleus, and the relationship between the rates of their activation and relaxation processes and the temperature sensitivities of these rates also seem to differ. In both muscles caffeine can convert activity-induced shortened of half-relaxation times into prolongations. In the soleus this effect is more pronounced at 30 than at 25 degrees C. At high temperature and twitch rates caffeine reduces treppe amplitude and duration without affecting the eventual twitch tension decline in the gastrocnemius while it greatly accelerates twitch tension decline in the soleus. In both muscles intrafiber Ca2+ movements are apparently major determinants of fatigue behavior.

Animals↗