University of Texas Medical Branch

About: University of Texas Medical Branch is a education organization based out in Galveston, Texas, United States. It is known for research contribution in the topics: Population & Virus. The organization has 22033 authors who have published 38268 publications receiving 1517502 citations. The organization is also known as: The University of Texas Medical Branch at Galveston & UTMB.

A simple method for removing the resin from epoxy-embedded tissue.

Abstract: Epoxy resins were first used as embedd ing media for electron microscopy by MaalCe and BirchAndersen (1) and Glauer t and Glauer t (2) and have since been employed extensively in Grea t Bri tain by Huxley (3) and Rober tson (4). Recen t improvements in processing and embedd ing techniques by Luft (5) and Finck (6) have led to their acceptance in many laboratories throughout the Uni t ed States. In correlated studies using electron and l ight microscopy it is usually necessary to remove the embedd ing mater ia l from the thick sections dest ined for convent ional l ight microscopy before they yield opt imal results in cellular detail and s taining qualities. Both xylol and acetone are excellent and rapid solvents for methacrylate , and removal of this plastic and subsequent staining for l ight microscopy are simple procedures (Bencosme et al., 7). Epoxy resins, however, are not soluble in s tandard organic solvents. Fisch and Hofmann (8) have studied the controlled chemical degrada t ion into soluble components of epoxy resins cured with phthal ic anhydride. Applying some of their findings we have developed a suitable solvent for use in tissue-resin systems.

M-currents and other potassium currents in bullfrog sympathetic neurones

Abstract: 1. Bullfrog lumbar sympathetic neurones were voltage-clamped in vitro through twin micro-electrodes. Four different outward (K(+)) currents could be identified: (i) a large sustained voltage-sensitive delayed rectifier current (I(K)) activated at membrane potentials more positive than -25 mV; (ii) a calcium-dependent sustained outward current (I(C)) activated at similar positive potentials and peaking at +20 to +60 mV; (iii) a transient current (I(A)) activated at membrane potentials more positive than -60 mV after a hyperpolarizing pre-pulse, but which was rapidly and totally inactivated at all potentials within its activation range; and (iv) a new K(+) current, the M-current (I(M)).2. I(M) was detected as a non-inactivating current with a threshold at -60 mV. The underlying conductance G(M) showed a sigmoidal activation curve between -60 and -10 mV, with half-activation at -35 mV and a maximal value (G(M)) of 84+/-14 (S.E.M.) nS per neurone. The voltage sensitivity of G(M) could be expressed in terms of a simple Boltzmann distribution for a single multivalent gating particle.3. I(M) activated and de-activated along an exponential time course with a time constant uniquely dependent upon voltage, maximizing at approximately 150 ms at -35 mV at 22 degrees C.4. Instantaneous current-voltage (I/V) curves were approximately linear in the presence of I(M), suggesting that the M-channels do not show appreciable rectification. However, the time- and voltage-dependent opening of the M-channels induced considerable rectification in the steady-state I/V curves recorded under both voltage-clamp and current-clamp modes between -60 and -25 mV. Both time- and voltage-dependent rectification in the voltage responses to current injection over this range could be predicted from the kinetic properties of I(M).5. It is suggested that I(M) exerts a strong potential-clamping effect on the behaviour of these neurones at membrane potentials subthreshold to excitation.

Immunization with SARS Coronavirus Vaccines Leads to Pulmonary Immunopathology on Challenge with the SARS Virus

Abstract: Background Severe acute respiratory syndrome (SARS) emerged in China in 2002 and spread to other countries before brought under control. Because of a concern for reemergence or a deliberate release of the SARS coronavirus, vaccine development was initiated. Evaluations of an inactivated whole virus vaccine in ferrets and nonhuman primates and a virus-like-particle vaccine in mice induced protection against infection but challenged animals exhibited an immunopathologic-type lung disease.