Total ear replantation.

Since the first report of successful microsurgical ear replantation in 1980, there have been 12 other cases reported in the English literature. As the number of trained microsurgeons increases, the opportunity to treat the amputated ear with microsurgical techniques should become more common. The reported cases have involved a variety of different mechanisms of injury and methods of treatment. There have been three techniques used to revascularize the amputated ear successfully: primary vascular repair, vein grafting, and use of the superficial temporal vessels as a pedicled vascular leash. Through our own experience and a review of the literature, we have been able to identify certain clinical characteristics that help dictate which technique to use. We report four cases of successful ear replantation, review the various techniques that have been used successfully, and provide treatment recommendations for future consideration.

Ethanol tolerance of immobilized brewers' yeast cells.

A method based on the survival of yeast cells subjected to an ethanol or heat shock was utilized to compare the stress resistance of free and carrageenan-immobilized yeast cells. Results demonstrated a significant increase of yeast survival against ethanol for immobilized cells as compared to free cells, while no marked difference in heat resistance was observed. When entrapped cells were released by mechanical disruption of the gel beads and submitted to the same ethanol stress, they exhibited a lower survival rate than entrapped cells, but a similar or slightly higher survival rate than free cells. The incidence of ethanol- or heat-induced respiratory-deficient mutants of entrapped cells was equivalent to that of control or non-stressed cells (1.3 +/- 0.5%) whereas ethanol- and heat-shocked free and released cells exhibited between 4.4% and 10.9% average incidence of respiration-deficient mutants. It was concluded that the carrageenan gel matrix provided a protection against ethanol, and that entrapped cells returned to normal physiological behaviour as soon as they were released. The cell growth rate was a significant factor in the resistance of yeast to high ethanol concentrations. The optimum conditions to obtain reliable and reproducible results involved the use of slow-growing cells after exhaustion of the sugar substrate.

Bilateral forearm and hand compartment syndrome following thrombolysis for acute myocardial infarction: a case report.

A patient suffering from a cocaine-induced myocardial infarction was treated with thrombolytic therapy and developed acute bilateral compartment syndromes of the upper extremities and hands from bleeding due to attempted bilateral radial artery cannulation. He was treated with emergent decompression of the forearm compartments and intrinsic muscles of the hands and recovered excellent hand function without significant neurologic or muscular damage. The problems encountered in the management of this case are detailed, and recommendations for prevention and therapy are discussed.

Studies of on-line viable yeast biomass with a capacitance biomass monitor.

A commercially available biomass monitor has been employed in a number of applications. For capacitance monitors, a relationship between capacitance measurement and cell counts or colony forming units has been reported in the literature. However, for use as an online instrument, a more practical correlation with the biomass concentration is needed. In this study, we followed the batch growth of brewer's yeast and a correlation with viable biomass concentration (g DW/L) was demonstrated. This correlation was utilized with the capacitance biomass monitor in a control loop to maintain setpoint biomass levels in a cyclic reactor under perturbations. Not only did the system demonstrate the capability of the biomass monitor to control biomass in such a system, but it also confirmed the correlation reported in our earlier work. (c) 1994 John Wiley & Sons, Inc.

2-Deoxy-D-glucose resistant yeast with altered sugar transport activity.

The transport of glucose and maltose in Saccharomyces cerevisiae was observed to occur by both high and low affinity transport systems. A spontaneously isolated 2-deoxy-D-glucose resistant mutant was observed to transport glucose and maltose only by the high affinity transport systems. Associated with this was an increase in the Vmax values, indicating derepression of the high affinity transport systems. The low affinity transport systems could not be detected. This mutant will be important in examining the repression regulatory and sugar transport mechanisms in yeast.

A study of ethanol tolerance in yeast.

The ethanol tolerance of yeast and other microorganisms has remained a controversial area despite the many years of study. The complex inhibition mechanism of ethanol and the lack of a universally accepted definition and method to measure ethanol tolerance have been prime reasons for the controversy. A number of factors such as plasma membrane composition, media composition, mode of substrate feeding, osmotic pressure, temperature, intracellular ethanol accumulation, and byproduct formation have been shown to influence the ethanol tolerance of yeast. Media composition was found to have a profound effect upon the ability of a yeast strain to ferment concentrated substrates (high osmotic pressure) and to ferment at higher temperatures. Supplementation with peptone-yeast extract, magnesium, or potassium salts has a significant and positive effect upon overall fermentation rates. An intracellular accumulation of ethanol was observed during the early stages of fermentation. As fermentation proceeds, the intracellular and extracellular ethanol concentrations become similar. In addition, increases in osmotic pressure are associated with increased intracellular accumulation of ethanol. However, it was observed that nutrient limitation, not increased intracellular accumulation of ethanol, is responsible to some extent for the decreases in growth and fermentation activity of yeast cells at higher osmotic pressure and temperature.

Microvascular free tissue transfer after arterial revascularization in the elderly: an alternative to amputation.

Extensive tissue loss associated with ischemia is a common problem in the elderly population with vascular insufficiency. This study involves 3 patients who underwent free tissue transfer following arterial revascularization for limb salvage. Latissimus dorsi, internal oblique muscles, and temporoparietal fascia free flaps were used. Two patients had the recipient vessel reconstituted by collaterals after complete atherosclerotic occlusion. There were no postoperative complications, and the reconstructive procedure never precipitated ischemia of the revascularized extremity. We conclude that free tissue transfers can be performed safely with good functional results in elderly patients. Such transfers should be considered an alternative to amputation and a rational step after arterial revascularization for limb salvage in patients with complex, nonhealing soft tissue defects.

Properties of hexose-transport regulatory mutants isolated from L6 rat myoblasts.

A hexose-transport regulatory mutant (D1/S4) was isolated from L6 rat myoblasts on the basis of its resistance to detachment and cell lysis in the presence of antibody and complement. Growth studies indicated that D1/S4 cells had a slower doubling time (29 h) compared with the parental L6 cells (22 h). Furthermore, after 9 days growth, less than 1% cell fusion was observed with D1/S4 cells, whereas 95% cell fusion was observed with the L6 cells. When the parental L6 cells were starved of glucose or treated with anti-L6 antibody, a significant increase in the Vmax, of 2-deoxy-D-glucose (dGlc) and 3-O-methyl-D-glucose (MeGlc) transport was observed. Although glucose-grown D1/S4 cells possessed normal hexose-transport activity, the above treatments had no effect on dGlc and MeGlc transport in these cells. Electrophoresis and immunoblotting studies revealed that D1/S4 cells possessed decreased amounts of a 112 kDa plasma-membrane protein. It is conceivable that this protein may play a role in triggering the antibody- and glucose-starvation-mediated activation of hexose transport and in myogenic differentiation. Unlike D1/S4, mutant F72, a mutant defective in the high-affinity hexose-transport system, was found to possess normal amounts of the 112 kDa protein. Although glucose starvation has no effect on the hexose-transport activity in this mutant, its hexose transport activity can be increased by antibody treatment. These studies with mutants suggest the involvement of regulatory components in the activation of hexose transport.

Intracellular ethanol accumulation in Saccharomyces cerevisiae during fermentation.

An intracellular accumulation of ethanol in Saccharomyces cerevisiae was observed during the early stages of fermentation (3 h). However, after 12 h of fermentation, the intracellular and extracellular ethanol concentrations were similar. Increasing the osmotic pressure of the medium caused an increase in the ratio of intracellular to extracellular ethanol concentrations at 3 h of fermentation. As in the previous case, the intracellular and extracellular ethanol concentrations were similar after 12 h of fermentation. Increasing the osmotic pressure also caused a decrease in yeast cell growth and fermentation activities. However, nutrient supplementation of the medium increased the extent of growth and fermentation, resulting in complete glucose utilization, even though intracellular ethanol concentrations were unaltered. These results suggest that nutrient limitation is a major factor responsible for the decreased growth and fermentation activities observed in yeast cells at higher osmotic pressures.

Effects of single doses of the converting enzyme inhibitor cilazapril in normal volunteers.

The new converting enzyme inhibitor cilazapril, or RO 31-2848, was evaluated in 14 healthy male volunteers. In a pilot study in two subjects, the inhibiting capacity of single oral doses of 5 and 10 mg on the pressure and heart rate response to exogenous angiotensin I was assessed. Both doses reduced the blood pressure response to angiotensin I to 10% of control within 45 min and for the 4 h tested. In the main study, 12 volunteers each received two single oral doses of cilazapril at a 2-week interval, and plasma converting enzyme and renin activity, blood angiotensin I, plasma immunoreactive angiotensin II and aldosterone were measured serially. Single doses of 1.25, 2.5, 5, and 10 mg of cilazapril were tested in groups of six subjects each. All doses inhibited plasma converting enzyme activity by 90% for at least 8 h and induced the expected pattern of changes of the renin-angiotensin-aldosterone system. Only slight dose-dependent variations in the effect were observed. Basic heart rate and blood pressure were not altered by any of the doses, which all were well tolerated. These data suggest that cilazapril is a very potent and long-acting new converting enzyme inhibitor.

Pharmacokinetics of the converting enzyme inhibitor cilazapril in normal volunteers and the relationship to enzyme inhibition: development of a mathematical model.

The pharmacokinetics of the new converting enzyme inhibitor cilazapril were investigated in 12 healthy male volunteers. Single oral doses of 1.25, 2.5, 5, and 10 mg of cilazapril were tested in groups of six subjects, each of whom received two different doses. A 2-week interval was allowed between treatments. Plasma levels of cilazaprilat, the active form of cilazapril, were measured for up to 3 days after drug administration. Peak plasma levels and 24-h areas under the curve (AUCs) were almost directly proportional to dose, and the elimination half-life (t1/2) during the first 8 h after dosing was 1.5 h. From 24 h on, there was a prolonged terminal phase with a t1/2 of approximately 50 h, and there was only slight dose-dependency during this phase. These data suggest that the pharmacokinetics of cilazapril are nonlinear. A physiologically realistic model based on saturable binding to converting enzyme was developed to account both for the drug kinetics and for the relationship of the kinetics to the dynamics of plasma converting enzyme inhibition. A number of conclusions relevant to the therapeutic application of cilazapril in hypertension are drawn from the data and from the pharmacokinetic-pharmacodynamic model.

Repeated administration of the converting enzyme inhibitor cilazapril to normal volunteers.

Cilazapril 1.25 and 5.0 mg p.o. q.d. was administered in double-blind fashion to two groups of six normal volunteers on 8 consecutive days. Blood pressure, heart rate, and plasma converting enzyme activity were measured each day prior to drug administration and up to 72 h after the last dose. Plasma renin activity, blood angiotensin I, plasma angiotensin II, and aldosterone as well as plasma cilazaprilat levels were determined on the first and the last day of active treatment at times 0, 4, and 24 h. The drug was very well tolerated by all volunteers. At 4 h postdrug, plasma converting enzyme activity was reduced in dose-dependent fashion on the first and the eighth day; plasma cilazaprilat levels were also clearly dose dependent. Nevertheless, 24 h postdrug cilazaprilat levels were similar on the first and last day of drug administration, and plasma converting enzyme activity was also stable throughout the 8 days. The various components of the renin-angiotensin system responded in the usual fashion. These results provide strong evidence that cilazapril is a very potent and highly effective converting enzyme inhibitor. Doses well below 5 mg/day will probably suffice for therapeutic efficacy. These data also confirm the hypothesis formulated in the preceding article, i.e., that there is no accumulation of the drug with repeated administration despite its long pharmacological half-life (t1/2).

Effect on blood pressure and the renin-angiotensin system of repeated doses of the converting enzyme inhibitor CGS 14824A.

A new, orally active angiotensin converting enzyme (ACE) inhibitor, CGS 14824A, was evaluated in 12 healthy male volunteers. Two groups each of 6 volunteers were given 5 or 10 mg once daily p.o. for 8 days. Four hours after the first and the last morning doses, plasma angiotensin II, aldosterone and plasma converting enzyme activity had fallen, while blood angiotensin I and plasma renin activity had risen. Throughout the study, more than 90% inhibition of ACE was found immediately before giving either the 5 or 10 mg dose and 50% blockade was still present 72 h following the last dose. Based on the determination of ACE, there was no evidence of drug accumulation. No significant change in blood pressure or heart rate was observed during the course of the study. CGS 14824A was an effective, orally active, long-lasting and well tolerated converting enzyme inhibitor.

Approaches used to examine the mechanism and regulation of hexose transport in rat myoblasts.

This review discusses some of the approaches and general criteria that we have used to examine the properties of the hexose transport system in undifferentiated L6 rat myoblasts. These approaches include studying the kinetics of hexose transport in whole cells and plasma membrane vesicles, the effects of various inhibitors on hexose transport, the isolation and characterization of hexose transport mutants, and the use of cytochalasin B (CB) to identify the transport component(s). Transport kinetics indicated that two transport systems are present in these cells. 2-Deoxy-D-glucose is transported primarily by the high affinity system, whereas 3-O-methyl-D-glucose is transported by the low affinity system. Furthermore, these two transport systems are inactivated to different extents by CB. CB has a higher binding affinity for the low affinity hexose transport system. The inhibitory effect of various hexose analogues also revealed the presence of two hexose transport systems. The effects of various ionophores and energy uncouplers on hexose transport suggest that the high affinity system is an active transport process, whereas the low affinity system is of the facilitated diffusion type. The high affinity system is also sensitive to sulfhydryl reagents, whereas the low affinity system is not. Further evidence for the presence of two transport systems comes from the characterization of hexose transport mutants. Two of the mutants isolated are shown to be defective in the high affinity transport system, but not in the low affinity transport system. These mutants are also defective in the CB low affinity binding site. Based on our results a tentative working model for hexose transport in L6 rat myoblasts is presented.

Hexose transport in plasma membrane vesicles prepared from L6 rat myoblasts.

Hexose transport in plasma membrane vesicles prepared from L6 rat myoblasts was shown to be stereospecific, activated by glucose starvation and occurred by both high and low affinity systems. Transport by the high affinity system was shown to occur by an active transport process. Furthermore, the high affinity system was shown to be defective in vesicles prepared from F72 cells (hexose transport mutant). These results indicate that the high affinity hexose transport system is retained in the plasma membrane vesicles. Thus plasma membrane vesicles could be of value in further characterization of the L6 high affinity hexose transport system, without interference from the various metabolic events occurring in whole cells.

Stimulation of hexose transport in L6 rat myoblasts by antibody and by glucose starvation.

Treatment of glucose-grown L6 rat myoblasts with rabbit or sheep anti-(L6-rat myoblast) antibody for 35 min or glucose starvation for at least 8 h results in a 2-fold increase in the Vmax. of 2-deoxy-D-glucose (dGlc) and 3-O-methyl-D-glucose uptake. In both cases, apparent transport affinities were not affected. Furthermore, once stimulation has occurred, further increases in hexose uptake could not be produced. Assays of antibody binding to whole cells suggested that the antibody is not internalized but remains bound on the cell surface. To elucidate the site and mechanism of antibody action, plasma-membrane vesicles from L6 cells were prepared. Anti-L6 antibody was found to cause a time- and dosage-dependent stimulation of dGlc transport in these vesicles. Maximum activation was achieved after 30 min exposure. This antibody-mediated activation could be inhibited by treatment of vesicles with various proteinase inhibitors. Treatment of vesicles with trypsin was also found to activate dGlc transport to levels observed with antibody. These results are virtually identical with those obtained with whole cells and suggest that antibody-mediated activation of hexose transport results from interaction of antibody with a specific membrane component(s).

Single and repeated dosing of the converting enzyme inhibitor perindopril to normal subjects.

The new orally active angiotensin converting enzyme (ACE) inhibitor perindopril (S9490-3) was evaluated in 18 normotensive men. In three subjects the pressor response to exogenous angiotensin I was tested. A 8 mg oral dose reduced the pressor response by greater than 80%. Single oral perindopril doses of 2, 4, 8, and 16 mg were given to groups of five subjects each. Eight and 16 mg decreased plasma ACE activity within 4 hours to less than 10% of control; 72 hours later, plasma ACE activity was still reduced by at least 40%. Doses of 4 and 8 mg po once a day were then given for 8 days to two groups of six subjects. Four hours after the first and the last morning doses, plasma angiotensin II, aldosterone, and plasma ACE activity fell significantly, whereas blood angiotensin I and plasma renin activity rose. There was no evidence of drug accumulation. No significant change in blood pressure or heart rate was observed. Thus in normotensive subjects, perindopril seems an effective, orally active, long-lasting ACE inhibitor.